fix: make chain-id flag not strictly required for tx commands

[technicallyty]

Description

chain-id's can be specified in a client config to be used in CLI commands. This PR changes the ChainID flag to no longer be explicitly required, as this value can come from clientCtx via config.

Closes: #9644

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[amaury1093]

Nice! Could you add a changelog entry?

[atheeshp]

pending on changelog

[codecov]

Codecov Report

Merging #10184 (72ad96b) into master (94377f1) will increase coverage by 0.00%.
The diff coverage is n/a.

❗ Current head 72ad96b differs from pull request most recent head b784b28. Consider uploading reports for the commit b784b28 to get more accurate results

@@           Coverage Diff           @@
##           master   #10184   +/-   ##
=======================================
  Coverage   63.72%   63.73%           
=======================================
  Files         573      573           
  Lines       53766    53764    -2     
=======================================
+ Hits        34263    34264    +1     
+ Misses      17555    17552    -3     
  Partials     1948     1948           

Impacted Files	Coverage Δ
client/flags/flags.go	21.81% <ø> (+0.76%)	⬆️
crypto/keys/internal/ecdsa/privkey.go	84.21% <0.00%> (+1.75%)	⬆️