fix: allow empty public keys

Description

Empty public keys would throw an error when calling SetSignatures. Public keys are optional and only needed in the first transaction to set it in state.

This should not break consensus and thus is okay as a minor release

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and please add links to any relevant follow up issues.

I have...

[ ] included the correct type prefix in the PR title
[ ] added ! to the type prefix if API or client breaking change
[ ] targeted the correct branch (see PR Targeting)
[ ] provided a link to the relevant issue or specification
[ ] followed the guidelines for building modules
[ ] included the necessary unit and integration tests
[ ] added a changelog entry to CHANGELOG.md
[ ] included comments for documenting Go code
[ ] updated the relevant documentation or specification
[ ] reviewed "Files changed" and left comments if necessary
[ ] confirmed all CI checks have passed

Reviewers Checklist

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I have...

[ ] confirmed the correct type prefix in the PR title
[ ] confirmed ! in the type prefix if API or client breaking change
[ ] confirmed all author checklist items have been addressed
[ ] reviewed state machine logic
[ ] reviewed API design and naming
[ ] reviewed documentation is accurate
[ ] reviewed tests and test coverage
[ ] manually tested (if applicable)

Codecov Report

Attention: 52 lines in your changes are missing coverage. Please review.

Comparison is base (e04d485) 65.55% compared to head (fdfb76a) 65.54%. Report is 4 commits behind head on release/v0.46.x-celestia.

Additional details and impacted files

[![Impacted file tree graph](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371/graphs/tree.svg?width=650&height=150&src=pr&token=QPoE0e3PbO&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg)](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg) ```diff @@ Coverage Diff @@ ## release/v0.46.x-celestia #371 +/- ## ============================================================ - Coverage 65.55% 65.54% -0.01% ============================================================ Files 666 666 Lines 71180 71213 +33 ============================================================ + Hits 46661 46680 +19 - Misses 21936 21945 +9 - Partials 2583 2588 +5 ``` | [Files](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg) | Coverage Δ | | |---|---|---| | [x/upgrade/keeper/keeper.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-eC91cGdyYWRlL2tlZXBlci9rZWVwZXIuZ28=) | `83.72% <100.00%> (ø)` | | | [x/auth/tx/builder.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-eC9hdXRoL3R4L2J1aWxkZXIuZ28=) | `82.35% <70.00%> (+0.29%)` | :arrow_up: | | [x/params/types/consensus\_params.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-eC9wYXJhbXMvdHlwZXMvY29uc2Vuc3VzX3BhcmFtcy5nbw==) | `0.00% <0.00%> (ø)` | | | [x/auth/client/cli/tx\_multisign.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-eC9hdXRoL2NsaWVudC9jbGkvdHhfbXVsdGlzaWduLmdv) | `0.00% <0.00%> (ø)` | | | [baseapp/abci.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-YmFzZWFwcC9hYmNpLmdv) | `59.93% <11.11%> (-0.67%)` | :arrow_down: | | [baseapp/options.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-YmFzZWFwcC9vcHRpb25zLmdv) | `56.66% <0.00%> (-2.99%)` | :arrow_down: | | [baseapp/params.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-YmFzZWFwcC9wYXJhbXMuZ28=) | `80.00% <0.00%> (-20.00%)` | :arrow_down: | | [baseapp/baseapp.go](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg#diff-YmFzZWFwcC9iYXNlYXBwLmdv) | `73.43% <5.55%> (-3.03%)` | :arrow_down: | ... and [1 file with indirect coverage changes](https://app.codecov.io/gh/celestiaorg/cosmos-sdk/pull/371/indirect-changes?src=pr&el=tree-more&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=celestiaorg)

celestiaorg / cosmos-sdk