HDFS-17834. Fix invalid HTTP links for DataNodes in IPv6 environment

[mynameis180]

Description of PR

This PR fixes HDFS-17834: HDFS NameNode Web UI generates invalid HTTP links for DataNodes in IPv6 environment.

Problem

The NameNode Web UI incorrectly handles IPv6 addresses in DataNode links:

1. Fails to encapsulate IPv6 addresses in square brackets [] as required by RFC 2732
2. Incorrectly parses IPv6 addresses, mistaking parts of the address for port numbers
3. Generates malformed, unclickable links that don't point to the DataNode's web interface

Solution

• Properly wrap IPv6 addresses in square brackets for URL construction
• Fix the address parsing logic to correctly separate IPv6 addresses from port numbers
• Ensure generated links follow RFC 2732 standards for IPv6 literal addresses in URLs

Example

Before: https://datanodeHostname:30 (invalid)
After: https://[1172:30:0:0:0:0:8a34]:50010 (valid)

How was this patch tested?

• Added unit tests for IPv6 address formatting in URL generation
• Tested with existing IPv4 addresses to ensure no regression
• Manual testing with IPv6 DataNode configurations
• Verified generated links are clickable and point to correct DataNode web interfaces

For code changes:

• Does the title or this PR starts with the corresponding JIRA issue id?
• Object storage: have the integration tests been executed and the endpoint declared according to the connector-specific documentation?
• If adding new dependencies to the code, are these dependencies licensed in a way that is compatible for inclusion under ASF 2.0?
• If applicable, have you updated the LICENSE, LICENSE-binary, NOTICE-binary files?

Note: This PR only contains code changes and no new dependencies were added.

[mynameis180]

retry pull

[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	20m 16s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	detsecrets	0m 0s		detect-secrets was not available.
+0 🆗	jshint	0m 0s		jshint was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
			_ branch-3.4 Compile Tests _
+0 🆗	mvndep	2m 48s		Maven dependency ordering for branch
+1 💚	mvninstall	39m 59s		branch-3.4 passed
+1 💚	shadedclient	82m 46s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+0 🆗	mvndep	0m 34s		Maven dependency ordering for patch
+1 💚	mvninstall	1m 45s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	shadedclient	38m 51s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	asflicense	0m 38s		The patch does not generate ASF License warnings.
		146m 35s

Subsystem	Report/Notes
Docker	ClientAPI=1.52 ServerAPI=1.52 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8080/1/artifact/out/Dockerfile
GITHUB PR	#8080
Optional Tests	dupname asflicense shadedclient codespell detsecrets jshint
uname	Linux 32bbff8fa0ba 5.15.0-160-generic #170-Ubuntu SMP Wed Oct 1 10:06:56 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.4 / e94407a
Max. process+thread count	527 (vs. ulimit of 5500)
modules	C: hadoop-hdfs-project/hadoop-hdfs hadoop-hdfs-project/hadoop-hdfs-rbf U: hadoop-hdfs-project
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8080/1/console
versions	git=2.25.1 maven=3.6.3
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