[FLINK-33289] Fix the conversion of InetSocketAddress to URL in Network utils to work with ipv6 address correctly

[caodizhou]

What is the purpose of the change

Fix the failure of creating a connection when the gateway address is an IPv6 address.

Brief change log

• Fix NetUtils.socketToUrl to work properly if the hostString in the socketAddress is an IPv6 address.

Verifying this change

• Add testIpv6SocketToUrl and testIpv4SocketToUrl in NetUtilsTest.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (yes / no)
• The serializers: (yes / no / don't know)
• The runtime per-record code paths (performance sensitive): (yes / no / don't know)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: (yes / no / don't know)
• The S3 file system connector: (yes / no / don't know)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[flinkbot]

CI report:

• b0d10c4 Azure: SUCCESS

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[KarmaGYZ]

Thanks for the pr @caodizhou . LGTM