fix(ampd): stellar tx receipt query and event check

[milapsheth]

Description

Soroban gateway rotation event

Todos

• Unit tests
• Manual tests
• Documentation
• Connect epics/issues

Steps to Test

Expected Behaviour

Other Notes

[codecov]

Codecov Report

Attention: Patch coverage is 94.44444% with 2 lines in your changes missing coverage. Please review.

Project coverage is 93.50%. Comparing base (c8c27d4) to head (d88206c).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
ampd/src/stellar/verifier.rs	90.90%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #647      +/-   ##
==========================================
- Coverage   93.50%   93.50%   -0.01%     
==========================================
  Files         243      243              
  Lines       34400    34412      +12     
==========================================
+ Hits        32165    32176      +11     
- Misses       2235     2236       +1     

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