Change to the network Sepolia in the TestClassV0 tests that are using the Goerli network

[stefanalfbo]

This PR is fixing the issue #1807.

New testdata for the classes has been fetched from the Sepolia network. All three tests has been using the Goerli network and the same class hashes, therefore all three tests are included in this PR,

• sn2core_test.go - TestClassV0
• class_test.go - TestClassV0Hash
• feeder_test.go - TestClassV0

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 75.04%. Comparing base (a923c90) to head (ca9c709).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1808      +/-   ##
==========================================
- Coverage   75.11%   75.04%   -0.08%     
==========================================
  Files          96       96              
  Lines        8183     8183              
==========================================
- Hits         6147     6141       -6     
- Misses       1513     1515       +2     
- Partials      523      527       +4     

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