deps: Remove wee_alloc optional dependency

[thanethomson]

Closes #1192.

wee_alloc was an optional dependency and an optimization anyways.

---

• Referenced an issue explaining the need for the change
• Updated all relevant documentation in docs
• Updated all code comments where relevant
• Wrote tests
• Added entry in .changelog/

[codecov-commenter]

Codecov Report

Merging #1201 (a6db49c) into main (e7f4978) will decrease coverage by 0.0%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##            main   #1201     +/-   ##
=======================================
- Coverage   67.0%   67.0%   -0.1%     
=======================================
  Files        219     219             
  Lines      20709   20708      -1     
=======================================
- Hits       13895   13892      -3     
- Misses      6814    6816      +2     

Impacted Files	Coverage Δ
light-client-js/src/lib.rs	1.8% <ø> (-1.9%)	⬇️
light-client-verifier/src/types.rs	38.1% <0.0%> (-0.9%)	⬇️
testgen/src/header.rs	83.5% <0.0%> (-0.6%)	⬇️
tendermint/src/node.rs	63.8% <0.0%> (-0.2%)	⬇️
testgen/src/validator.rs	87.5% <0.0%> (+0.7%)	⬆️
testgen/src/vote.rs	84.8% <0.0%> (+0.8%)	⬆️
tendermint/src/timeout.rs	85.9% <0.0%> (+1.7%)	⬆️

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