isolate packet fee distribution for on acknowledgement and on timeout into separate functions

[colin-axner]

Description

Reduces the complexity contained in DistributePacketFees and DistributePacketFeesOnAcknowledgement in anticipation of #1251

closes: #XXXX

---

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-commenter]

Codecov Report

Merging #1253 (7a9ad20) into main (e59a6d2) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1253   +/-   ##
=======================================
  Coverage   80.15%   80.16%           
=======================================
  Files         166      166           
  Lines       11943    11949    +6     
=======================================
+ Hits         9573     9579    +6     
  Misses       1912     1912           
  Partials      458      458           

Impacted Files	Coverage Δ
modules/apps/29-fee/keeper/escrow.go	88.88% <100.00%> (+0.60%)	⬆️