[Port 2.1] Hide part of code behind feature flag (#22529)

[tyler-cai-microsoft]

Original: #22529
Part of a hotfix

There is some minimum sequence number shenanigans going on. Not exactly sure, but we want to be able to safely turn off the feature.

[msfluid-bot]

⯅ @fluid-example/bundle-size-tests: +568 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	456.97 KB	457.08 KB	⯅ +116 Bytes
azureClient.js	554.74 KB	554.86 KB	⯅ +131 Bytes
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	258.18 KB	258.27 KB	⯅ +93 Bytes
fluidFramework.js	405.94 KB	405.95 KB	⯅ +14 Bytes
loader.js	134.04 KB	134.05 KB	⯅ +14 Bytes
map.js	42.13 KB	42.14 KB	⯅ +7 Bytes
matrix.js	145.61 KB	145.62 KB	⯅ +7 Bytes
odspClient.js	522.88 KB	523.01 KB	⯅ +130 Bytes
odspDriver.js	97.55 KB	97.57 KB	⯅ +21 Bytes
odspPrefetchSnapshot.js	42.61 KB	42.62 KB	⯅ +14 Bytes
sharedString.js	162.62 KB	162.63 KB	⯅ +7 Bytes
sharedTree.js	396.45 KB	396.46 KB	⯅ +7 Bytes
Total Size	3.29 MB	3.29 MB	⯅ +568 Bytes

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Baseline commit: 1571e0c

Generated by 🚫 dangerJS against b24f545

[frankmueller-microsoft]

Approved patch