fix(client): exactOptionalPropertyTypes clean up

[jason-ha]

Select changes required to support new Presence package being built with exactOptionalPropertyTypes: true.

When exactOptionalPropertyTypes is false, a property specified as optional (via ?) may be assigned undefined. When true that is not allowed.

Update types to explicitly allow undefined (no effective type change as most build continues to use exactOptionalPropertyTypes: false) or to properly respect not setting undefined. The latter is an implementation change but conforms to declared specification.

Make fix(client): make IFluidDataStoreRuntime.idCompressor non-optional but retain undefined possibility. This matches existing implementations.

PrefetchDocumentStorageService - use explicit return type to avoid inference that may infer maximumCacheDurationMs as | undefined which could later be inconsistent with exactOptionalPropertyTypes: true.

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluidframework-docs@0.25.0 ci:linkcheck /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test ci:start 1313 linkcheck:full

1: starting server using command "npm run ci:start"
and when url "[ 'http://127.0.0.1:1313' ]" is responding with HTTP status code 200
running tests using command "npm run linkcheck:full"


> fluidframework-docs@0.25.0 ci:start
> http-server ./public --port 1313 --silent


> fluidframework-docs@0.25.0 linkcheck:full
> npm run linkcheck:fast -- --external


> fluidframework-docs@0.25.0 linkcheck:fast
> linkcheck http://localhost:1313 --skip-file skipped-urls.txt --external

Crawling...

Stats:
  404342 links
    3145 destination URLs
       2 URLs ignored
       0 warnings
       0 errors

[msfluid-bot]

⯅ @fluid-example/bundle-size-tests: +345 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	460.2 KB	460.24 KB	⯅ +38 Bytes
azureClient.js	558.17 KB	558.24 KB	⯅ +74 Bytes
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	260.96 KB	260.97 KB	⯅ +17 Bytes
fluidFramework.js	401.34 KB	401.35 KB	⯅ +14 Bytes
loader.js	134.24 KB	134.25 KB	⯅ +14 Bytes
map.js	42.44 KB	42.44 KB	⯅ +7 Bytes
matrix.js	146.59 KB	146.59 KB	⯅ +7 Bytes
odspClient.js	525.47 KB	525.54 KB	⯅ +74 Bytes
odspDriver.js	97.72 KB	97.76 KB	⯅ +43 Bytes
odspPrefetchSnapshot.js	42.78 KB	42.81 KB	⯅ +36 Bytes
sharedString.js	163.28 KB	163.29 KB	⯅ +7 Bytes
sharedTree.js	391.8 KB	391.81 KB	⯅ +7 Bytes
Total Size	3.3 MB	3.3 MB	⯅ +345 Bytes

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Baseline commit: c3a4565

Generated by 🚫 dangerJS against 646b881