refactor(root): move encoding convertion to fromRawTx for near

[alebusse]

Moved the logic to convert from hex to base64 encoding from bitgo(core) to accountLib
Added unit tests

STLX-16118

[codecov]

Codecov Report

Merging #2257 (f668a9a) into master (bfdc82c) will increase coverage by 85.99%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           master    #2257       +/-   ##
===========================================
+ Coverage        0   85.99%   +85.99%     
===========================================
  Files           0      185      +185     
  Lines           0     9437     +9437     
  Branches        0     1406     +1406     
===========================================
+ Hits            0     8115     +8115     
- Misses          0      838      +838     
- Partials        0      484      +484     

Flag	Coverage Δ
unit	85.99% <100.00%> (?)

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Impacted Files	Coverage Δ
modules/account-lib/src/coin/near/constants.ts	100.00% <100.00%> (ø)
modules/account-lib/src/coin/near/transaction.ts	83.33% <100.00%> (ø)
modules/account-lib/src/coin/cspr/index.ts	100.00% <0.00%> (ø)
...odules/account-lib/src/coin/dot/transferBuilder.ts	79.74% <0.00%> (ø)
...odules/account-lib/src/coin/stx/sendmanyBuilder.ts	76.19% <0.00%> (ø)
modules/account-lib/src/coin/trx/enum.ts	100.00% <0.00%> (ø)
modules/account-lib/src/coin/hbar/index.ts	100.00% <0.00%> (ø)
...odules/account-lib/src/coin/celo/stakingBuilder.ts	93.33% <0.00%> (ø)
modules/account-lib/src/coin/sol/index.ts	100.00% <0.00%> (ø)
...ount-lib/src/coin/stx/transactionBuilderFactory.ts	80.00% <0.00%> (ø)
... and 177 more