fix(tm2): Fix the endpoint /tx?hash= to make it work

[linhpn99]

From issue : #2489

I found an issue with the code segment parsing arguments from the request that did not support base64 encoding, so I implemented logic to handle it. If there are any inconsistencies, please share the opinion

Contributors' checklist...

• Added new tests, or not needed, or not feasible
• Provided an example (e.g. screenshot) to aid review or the PR is self-explanatory
• Updated the official documentation or not needed
• No breaking changes were made, or a BREAKING CHANGE: xxx message was included in the description
• Added references to related issues and PRs
• Provided any useful hints for running manual tests
• Added new benchmarks to generated graphs, if any. More info here.

[codecov]

Codecov Report

Attention: Patch coverage is 64.00000% with 9 lines in your changes missing coverage. Please review.

Project coverage is 62.98%. Comparing base (f04ec89) to head (9f13812).
Report is 90 commits behind head on master.

Files with missing lines	Patch %	Lines
tm2/pkg/bft/rpc/lib/server/handlers.go	64.00%	6 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2518      +/-   ##
==========================================
+ Coverage   60.44%   62.98%   +2.54%     
==========================================
  Files         563      567       +4     
  Lines       75159    82601    +7442     
==========================================
+ Hits        45427    52026    +6599     
- Misses      26343    27112     +769     
- Partials     3389     3463      +74     

Flag	Coverage Δ
contribs/gnodev	60.57% <ø> (-0.89%)	⬇️
contribs/gnofaucet	15.77% <ø> (+0.45%)	⬆️
gno.land	67.37% <ø> (+0.15%)	⬆️
gnovm	67.36% <ø> (+2.89%)	⬆️
misc/genstd	79.72% <ø> (-0.83%)	⬇️
tm2	62.45% <64.00%> (+0.40%)	⬆️

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[thehowl]

Thanks, some work to be done for a proper fix.

[leohhhn]

#2333 (comment)

[jefft0]

Removed the "review team" label because this is already reviewed by core devs.

[thehowl]

I had to be convinced of a few things, so cloned and tested it out. I committed some clarifications, but it looks good overall.

cc/ @zivkovicmilos for a final review.