Remove checks that are not in the onchain contract

[pirapira]

TokenNetworkRegistry.createERC20() succeeds even when the stored
chain_id value is different from the current chain_id of the blockchain.

Since the proxies should not check what's not checked onchain,
I'm removing the checks that do not exist in the onchain contracts.

This PR comes from this conversation #4936 (comment)

Description

Please, describe what this PR does in detail:

• If it's a bug fix, detail the root cause of the bug and how this PR fixes it.

It's a bug fix. Before this PR, the proxy failed even when the transaction would succeed.

PR review check list

Quality check list that cannot be automatically verified.

• Safety
  • The changes respect the necessary conditions for safety (https://raiden-network-specification.readthedocs.io/en/latest/smart_contracts.html#protocol-values-constraints)
• Code quality
  • Error conditions are handled
  • Exceptions are propagated to the correct parent greenlet
  • Exceptions are correctly classified as recoverable or unrecoverable
• Compatibility
  • State changes are forward compatible
  • Transport messages are backwards and forward compatible
• Commits
  • Have good messages
  • Squashed unecessary commits
• If it's a bug fix:
  • Regression test for the bug
    • Properly covers the bug
    • If an integration test is used, it could not be written as a unit test
• Documentation
  • A new CLI flag was introduced, is there documentation that explains usage?
• Specs
  • If this is a protocol change, are the specs updated accordingly? If so, please link PR from the specs repo.
• Is it a user facing feature/bug fix?
  • Changelog entry has been added

[codecov]

Codecov Report

Merging #4956 into develop will decrease coverage by 0.01%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #4956      +/-   ##
===========================================
- Coverage    80.47%   80.45%   -0.02%     
===========================================
  Files          120      120              
  Lines        14603    14599       -4     
  Branches      2265     2263       -2     
===========================================
- Hits         11752    11746       -6     
  Misses        2185     2185              
- Partials       666      668       +2

Impacted Files	Coverage Δ
raiden/network/proxies/token_network_registry.py	53.76% <ø> (+1.13%)	⬆️
raiden/storage/serialization/types.py	59.7% <0%> (-8.96%)	⬇️
raiden/tasks.py	67.64% <0%> (-2.95%)	⬇️
raiden/utils/echo_node.py	67.79% <0%> (-1.7%)	⬇️
raiden/network/proxies/token_network.py	50.06% <0%> (-0.25%)	⬇️
raiden/transfer/channel.py	89.21% <0%> (-0.23%)	⬇️
raiden/transfer/mediated_transfer/mediator.py	90.44% <0%> (ø)	⬆️
raiden/network/transport/matrix/transport.py	80.64% <0%> (+0.3%)	⬆️
raiden/api/python.py	68.61% <0%> (+0.53%)	⬆️
raiden/transfer/node.py	94.79% <0%> (+0.54%)	⬆️
... and 1 more

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[LefterisJP]

LGTM, I agree with this change