chore: update colors of transaction feed and points history icons

[kathaypacific]

Description

This is planned for the transaction feed work but it also affects beefy, so I thought I'd just do it now. Kayla confirmed she is confident that she wants to go through with these changes (they're also in the demo designs) - rationale being taking away some color will bring more emphasis to the network icons.

Test plan

Related issues

• Fixes RET-1293

Backwards compatibility

Y

Network scalability

If a new NetworkId and/or Network are added in the future, the changes in this PR will:

• Continue to work without code changes, OR trigger a compilation error (guaranteeing we find it when a new network is added)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.11%. Comparing base (ed4ee81) to head (0187172).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6450      +/-   ##
==========================================
- Coverage   89.12%   89.11%   -0.02%     
==========================================
  Files         733      733              
  Lines       31909    31904       -5     
  Branches     6098     5783     -315     
==========================================
- Hits        28439    28430       -9     
- Misses       3275     3427     +152     
+ Partials      195       47     -148     

Files with missing lines	Coverage Δ
src/components/ContactCircle.tsx	100.00% <100.00%> (ø)
src/icons/Activity.tsx	100.00% <100.00%> (ø)
src/icons/MagicWand.tsx	100.00% <100.00%> (ø)
src/points/cardDefinitions.tsx	76.27% <ø> (ø)
src/transactions/feed/TransactionFeedItemImage.tsx	95.91% <ø> (ø)

... and 67 files with indirect coverage changes

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