x/feegrant remove height base expiration

[aleem1314]

Description

ref: #9115

Get rid of block height in ExportGenesis and remove height support in general and get rid of PrepareForExport method from FeeAllowanceI interface.

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #9206 (18ce215) into master (42a4e4b) will increase coverage by 0.03%.
The diff coverage is 88.23%.

❗ Current head 18ce215 differs from pull request most recent head cc2f1e8. Consider uploading reports for the commit cc2f1e8 to get more accurate results

@@            Coverage Diff             @@
##           master    #9206      +/-   ##
==========================================
+ Coverage   60.13%   60.16%   +0.03%     
==========================================
  Files         595      594       -1     
  Lines       37185    37106      -79     
==========================================
- Hits        22360    22325      -35     
+ Misses      12846    12805      -41     
+ Partials     1979     1976       -3     

Impacted Files	Coverage Δ
x/feegrant/types/filtered_fee.go	0.00% <ø> (ø)
x/feegrant/types/grant.go	70.37% <ø> (+26.18%)	⬆️
x/feegrant/types/periodic_fee.go	68.42% <77.77%> (+12.17%)	⬆️
x/feegrant/genesis.go	90.47% <100.00%> (-0.44%)	⬇️
x/feegrant/simulation/genesis.go	79.48% <100.00%> (ø)
x/feegrant/simulation/operations.go	77.19% <100.00%> (+0.20%)	⬆️
x/feegrant/types/basic_fee.go	88.23% <100.00%> (+13.23%)	⬆️
x/feegrant/keeper/keeper.go	85.05% <0.00%> (ø)
x/bank/types/balance.go	89.18% <0.00%> (+2.52%)	⬆️

[blushi]

Looks good overall but could you update the ADR as well?

[technicallyty]

LGTM 🚀