feat: fetch jwk considering goroutine exit

[shiki-tak]

Description

• Terminate FetchJWK's goroutine on shutdown.
• fetch_intervals does not need to be included in ProvidersConfig, so I removed it.

Motivation and context

How has this been tested?

Screenshots (if appropriate):

Checklist:

• [ ] I followed the contributing guidelines and code of conduct.
• [ ] I have added a relevant changelog to CHANGELOG.md
• [ ] I have added tests to cover my changes.
• [ ] I have updated the documentation accordingly.
• [ ] I have updated API documentation client/docs/swagger-ui/swagger.yaml

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 63.63636% with 12 lines in your changes are missing coverage. Please review.

:exclamation: No coverage uploaded for pull request base (feat/zkauth@df06ee1). Click here to learn what that means.

Additional details and impacted files

[](https://app.codecov.io/gh/Finschia/finschia-sdk/pull/1280?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Finschia) ```diff @@ Coverage Diff @@ ## feat/zkauth #1280 +/- ## ============================================== Coverage ? 69.58% ============================================== Files ? 659 Lines ? 68333 Branches ? 0 ============================================== Hits ? 47548 Misses ? 18536 Partials ? 2249 ``` | [Files](https://app.codecov.io/gh/Finschia/finschia-sdk/pull/1280?dropdown=coverage&src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Finschia) | Coverage Δ | | |---|---|---| | [x/zkauth/types/config.go](https://app.codecov.io/gh/Finschia/finschia-sdk/pull/1280?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Finschia#diff-eC96a2F1dGgvdHlwZXMvY29uZmlnLmdv) | `0.00% <0.00%> (ø)` | | | [x/zkauth/keeper/keeper.go](https://app.codecov.io/gh/Finschia/finschia-sdk/pull/1280?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Finschia#diff-eC96a2F1dGgva2VlcGVyL2tlZXBlci5nbw==) | `66.26% <67.74%> (ø)` | |