WiP: Add invalid post malfeasance

[fasmat]

Motivation

Closes #6141

Description

Test Plan

TODO

• [ ] Explain motivation or link existing issue(s)
• [ ] Test changes and document test plan
• [ ] Update documentation as needed
• [ ] Update changelog as needed

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 82 lines in your changes missing coverage. Please review.

Project coverage is 81.3%. Comparing base (5737fc4) to head (e84b2f5).

Files with missing lines	Patch %	Lines
activation/wire/malfeasance_invalid_post.go	0.0%	82 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #6308 +/- ## ========================================= - Coverage 81.6% 81.3% -0.3% ========================================= Files 313 314 +1 Lines 34937 35019 +82 ========================================= - Hits 28517 28503 -14 - Misses 4579 4669 +90 - Partials 1841 1847 +6 ```

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