Add portOpenRetries to server.xml files where it is missing in the com.ibm.ws.grpc_fat project

[pnicolucci]

Some server.xml files in this FAT bucket use fatTestCommon.xml and define the defaultHttpEndpoint, if using fatTestPorts.xml then the defaultHttpEndpoint would have portOpenRetries set to 60 to help with intermittent port bind issues.

This issue will add portOpenRetries where it is missing.