Allow whitespace in metric tag values

[markushi]

📜 Description

see getsentry/develop#1171
and getsentry/relay#3174
and getsentry/sentry-python#2775

💡 Motivation and Context

Whitespace is fine.

#skip-changelog
-- as the feature hasn't been released yet.

💚 How did you test it?

📝 Checklist

• I reviewed the submitted code.
• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

🔮 Next steps

[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	388.76 ms	467.24 ms	78.49 ms
Size	1.70 MiB	2.28 MiB	590.89 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
8fd337b	349.16 ms	459.22 ms	110.06 ms
86f0096	381.33 ms	476.58 ms	95.25 ms
2a3dd50	363.61 ms	440.18 ms	76.57 ms
2465853	411.39 ms	461.10 ms	49.72 ms
5e04ee8	380.63 ms	501.84 ms	121.21 ms
c554ca2	364.98 ms	433.64 ms	68.66 ms
4e29063	376.38 ms	390.98 ms	14.60 ms
a3c77bc	375.80 ms	445.85 ms	70.06 ms
4e260b3	378.73 ms	454.18 ms	75.45 ms
eecfab6	399.27 ms	461.82 ms	62.55 ms

App size

Revision	Plain	With Sentry	Diff
8fd337b	1.72 MiB	2.27 MiB	555.00 KiB
86f0096	1.72 MiB	2.29 MiB	576.50 KiB
2a3dd50	1.72 MiB	2.27 MiB	555.05 KiB
2465853	1.70 MiB	2.27 MiB	583.82 KiB
5e04ee8	1.70 MiB	2.27 MiB	584.64 KiB
c554ca2	1.70 MiB	2.27 MiB	582.25 KiB
4e29063	1.72 MiB	2.29 MiB	578.38 KiB
a3c77bc	1.72 MiB	2.29 MiB	577.53 KiB
4e260b3	1.72 MiB	2.27 MiB	554.95 KiB
eecfab6	1.72 MiB	2.27 MiB	558.56 KiB

Previous results on branch: fix/metrics-tag-value-normalization

Startup times

Revision	Plain	With Sentry	Diff
6fd4fb7	420.93 ms	460.26 ms	39.33 ms
fa3b33e	434.32 ms	492.92 ms	58.60 ms

App size

Revision	Plain	With Sentry	Diff
6fd4fb7	1.70 MiB	2.28 MiB	590.44 KiB
fa3b33e	1.70 MiB	2.28 MiB	590.72 KiB