HBASE-29541 Removing unnecessary sanitization in throttle metrics

[sidkhillon]

Removes some unnecessary sanitization we were doing in the throttle metrics reporting. Also, removes the null handling as those values should never be null.

[hgromer]

This looks good to me, cc @rmdmattingly @charlesconnell, any chance you could take a look at this? For context, we don't do this type of sanitation anywhere else in the code, and were worried of any potential overhead

[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.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	hbaseanti	0m 0s		Patch does not have any anti-patterns.
			_ master Compile Tests _
+1 💚	mvninstall	3m 10s		master passed
+1 💚	compile	3m 18s		master passed
+1 💚	checkstyle	0m 36s		master passed
+1 💚	spotbugs	1m 32s		master passed
+1 💚	spotless	0m 49s		branch has no errors when running spotless:check.
			_ Patch Compile Tests _
+1 💚	mvninstall	2m 55s		the patch passed
+1 💚	compile	3m 17s		the patch passed
+1 💚	javac	3m 17s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 37s		hbase-server: The patch generated 0 new + 0 unchanged - 2 fixed = 0 total (was 2)
+1 💚	spotbugs	1m 37s		the patch passed
+1 💚	hadoopcheck	11m 23s		Patch does not cause any errors with Hadoop 3.3.6 3.4.0.
+1 💚	spotless	0m 44s		patch has no errors when running spotless:check.
			_ Other Tests _
+1 💚	asflicense	0m 11s		The patch does not generate ASF License warnings.
		37m 53s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7238/2/artifact/yetus-general-check/output/Dockerfile
GITHUB PR	#7238
Optional Tests	dupname asflicense javac spotbugs checkstyle codespell detsecrets compile hadoopcheck hbaseanti spotless
uname	Linux e71d6b61e58f 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	master / 4b7b396
Default Java	Eclipse Adoptium-17.0.11+9
Max. process+thread count	85 (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-7238/2/console
versions	git=2.34.1 maven=3.9.8 spotbugs=4.7.3
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[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 29s		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 _
			_ master Compile Tests _
+1 💚	mvninstall	3m 5s		master passed
+1 💚	compile	1m 5s		master passed
+1 💚	javadoc	0m 28s		master passed
+1 💚	shadedjars	6m 10s		branch has no errors when building our shaded downstream artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	3m 7s		the patch passed
+1 💚	compile	0m 59s		the patch passed
+1 💚	javac	0m 59s		the patch passed
+1 💚	javadoc	0m 27s		the patch passed
+1 💚	shadedjars	6m 7s		patch has no errors when building our shaded downstream artifacts.
			_ Other Tests _
+1 💚	unit	221m 39s		hbase-server in the patch passed.
		248m 37s

Subsystem	Report/Notes
Docker	ClientAPI=1.43 ServerAPI=1.43 base: https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7238/2/artifact/yetus-jdk17-hadoop3-check/output/Dockerfile
GITHUB PR	#7238
Optional Tests	javac javadoc unit compile shadedjars
uname	Linux a09b28a819fb 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	master / 4b7b396
Default Java	Eclipse Adoptium-17.0.11+9
Test Results	https://ci-hbase.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-7238/2/testReport/
Max. process+thread count	4795 (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-7238/2/console
versions	git=2.34.1 maven=3.9.8
Powered by	Apache Yetus 0.15.0 https://yetus.apache.org

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