feat: invariants for rollapp and sequencer modules

[mtsitrin]

Description

---

Closes #421

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.

PR review checkboxes:

I have...

• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Targeted PR against the correct branch
• included the correct type prefix in the PR title
• Linked to the GitHub issue with discussion and accepted design
• Targets only one GitHub issue
• Wrote unit and integration tests
• Wrote relevant migration scripts if necessary
• All CI checks have passed
• Added relevant godoc comments

SDK Checklist

• Import/Export Genesis
• Registered Invariants
• Registered Events
• Updated openapi.yaml
• No usage of go map
• No usage of time.Now()
• Used fixed point arithmetic and not float arithmetic
• Avoid panicking in Begin/End block as much as possible
• No unexpected math Overflow
• Used sendCoin and not SendCoins
• Out-of-block compute is bounded
• No serialized ID at the end of store keys

Full security checklist here

For Reviewer:

• Confirmed the correct type prefix in the PR title
• Reviewers assigned
• Confirmed all author checklist items have been addressed

---;

After reviewer approval:

• In case the PR targets the main branch, PR should not be squash merge in order to keep meaningful git history.
• In case the PR targets a release branch, PR must be rebased.

[codecov]

Codecov Report

Attention: Patch coverage is 73.94137% with 80 lines in your changes are missing coverage. Please review.

Project coverage is 30.41%. Comparing base (86db62a) to head (32bb1d5).
Report is 1 commits behind head on main.

Files	Patch %	Lines
x/rollapp/keeper/invariants.go	65.06%	38 Missing and 13 partials ⚠️
x/sequencer/keeper/invariants.go	65.67%	17 Missing and 6 partials ⚠️
...llapp/keeper/block_height_to_finalization_queue.go	80.64%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #603      +/-   ##
==========================================
+ Coverage   29.97%   30.41%   +0.44%     
==========================================
  Files         199      201       +2     
  Lines       28178    28451     +273     
==========================================
+ Hits         8446     8654     +208     
- Misses      18405    18449      +44     
- Partials     1327     1348      +21     

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[mtsitrin]

proposer will be refactored to flag here: #614

The base branch was changed.