fix(cdc): failed to start when connects to pd with multiple endpoints and the 1st endpoint is not available (#4779)

[ti-chi-bot]

This is an automated cherry-pick of #4779

What problem does this PR solve?

Issue Number: close #4777

What is changed and how it works?

Changed:

remove the grpcTLSOption in etcd client config,

how it works:

etcd-io/etcd#11184 have provide an workaround to set authority to deal with the problem indicated in etcd-io/etcd#11180, what it does it to create an TransportCredentialsWithDialer interface which wraps the original grpccredentials.TransportCredentials. and its implementation here, this TransportCredentialsWithDialer will set authority to the corresponding enpoint at ClientHandshake period first, and then delegate other logic to original TransportCredentials, so as to ensure the authority is correct.
But if we set grpcTLSOption in dialOptions, this will overwrite the existing TransportCredentialsWithDialer with original grpc TransportCredentials.

tiflow/pkg/security/credential.go

Lines 52 to 57 in 20626ba

	func (s *Credential) ToGRPCDialOption() (grpc.DialOption, error) {
	tlsCfg, err := s.ToTLSConfig()
	if err != nil || tlsCfg == nil {
	return grpc.WithInsecure(), err
	}
	return grpc.WithTransportCredentials(credentials.NewTLS(tlsCfg)), nil

This PR will remove the the grpcTLSOption in etcd client config, thus won't overwrite the existing TransportCredentialsWithDialer.

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Code changes

• Has exported function/method change
• Has exported variable/fields change
• Has interface methods change
• Has persistent data change

Side effects

• Possible performance regression
• Increased code complexity
• Breaking backward compatibility

Related changes

• Need to cherry-pick to the release branch
• Need to update the documentation
• Need to update key monitor metrics in both TiCDC document and official document

Release note

fix the issue that ticdc failed to start when connects to  multiple pd endpoints with tls-enabled and the 1st endpoint is not available

[ti-chi-bot]

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[codecov-commenter]

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