HBASE-29093 Load userSnapshots.jsp only on master status page

[PDavid]

Before HBase UI always tried to load userSnapshots.jsp with an AJAX request on all UI pages - NOK.

This happened even on RegionServer UI or REST UI where this call always failed with HTTP 500.

From now on HBase UI only loads userSnapshots.jsp when the Snapshots tab (div with tab_userSnapshots ID) exists on the page.

Also did a minor improvement to tab.js: use const instead of var as var has so many problems:

With block-level scope, no hoisting, and the ability to declare constants, let and const make code more predictable, maintainable, and less error-prone. By using let and const instead of var, developers can avoid common pitfalls and write more declarative code.

Also fixed a whitespace.

(cherry picked from commit ed007404b0f31a51e2c5960c21340993073b7f06)

[PDavid]

This is a backport of #6627 on branch-3.

Tested this locally the same way as described here: #6627 (comment)

[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 28s		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 Compile Tests _
+1 💚	mvninstall	3m 10s		branch-3 passed
+1 💚	spotless	0m 45s		branch has no errors when running spotless:check.
			_ Patch Compile Tests _
+1 💚	mvninstall	2m 55s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	spotless	0m 43s		patch has no errors when running spotless:check.
			_ Other Tests _
+1 💚	asflicense	0m 10s		The patch does not generate ASF License warnings.
		9m 33s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-6698/1/artifact/yetus-general-check/output/Dockerfile
GITHUB PR	#6698
Optional Tests	dupname asflicense javac codespell detsecrets jshint spotless
uname	Linux 28a5b51fc126 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	branch-3 / 00cc87d
Default Java	Eclipse Adoptium-17.0.11+9
Max. process+thread count	82 (vs. ulimit of 30000)
modules	C: hbase-server U: hbase-server
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-6698/1/console
versions	git=2.34.1 maven=3.9.8
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[Apache-HBase]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 49s		Docker mode activated.
-0 ⚠️	yetus	0m 3s		Unprocessed flag(s): --brief-report-file --spotbugs-strict-precheck --author-ignore-list --blanks-eol-ignore-file --blanks-tabs-ignore-file --quick-hadoopcheck
			_ Prechecks _
			_ branch-3 Compile Tests _
+1 💚	mvninstall	4m 15s		branch-3 passed
+1 💚	javadoc	0m 47s		branch-3 passed
			_ Patch Compile Tests _
+1 💚	mvninstall	4m 50s		the patch passed
+1 💚	javadoc	0m 46s		the patch passed
			_ Other Tests _
-1 ❌	unit	281m 32s	/patch-unit-hbase-server.txt	hbase-server in the patch failed.
		297m 39s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-6698/1/artifact/yetus-jdk17-hadoop3-check/output/Dockerfile
GITHUB PR	#6698
Optional Tests	javac javadoc unit
uname	Linux c778dcde6f55 5.4.0-1103-aws #111~18.04.1-Ubuntu SMP Tue May 23 20:04:10 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/hbase-personality.sh
git revision	branch-3 / 00cc87d
Default Java	Eclipse Adoptium-17.0.11+9
Test Results	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-6698/1/testReport/
Max. process+thread count	4420 (vs. ulimit of 30000)
modules	C: hbase-server U: hbase-server
Console output	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-6698/1/console
versions	git=2.34.1 maven=3.9.8
Powered by	Apache Yetus 0.15.0 https://yetus.apache.org

This message was automatically generated.

[PDavid]

Some tests failed in the PR build but for me those tests look unrelated.