Allow for No-Op AccountSet SetFlag and ClearFlag values

[nkramer44]

Fixes #477

[codecov]

Codecov Report

Merging #479 (64bd3be) into main (42047e1) will increase coverage by 0.03%.
The diff coverage is 94.44%.

@@             Coverage Diff              @@
##               main     #479      +/-   ##
============================================
+ Coverage     90.48%   90.52%   +0.03%     
- Complexity     1473     1489      +16     
============================================
  Files           289      289              
  Lines          4184     4220      +36     
  Branches        339      347       +8     
============================================
+ Hits           3786     3820      +34     
  Misses          277      277              
- Partials        121      123       +2     

Files Changed	Coverage Δ
...org/xrpl/xrpl4j/model/transactions/AccountSet.java	95.00% <94.44%> (-0.46%)	⬇️