Validate Input to rehydrateDetachedContainerFromSnapshot

[anthony-murphy]

Validates that the string passed to rehydrateDetachedContainerFromSnapshot is of the correct format, rather than assuming via cast which can lead to random failures. Also add a unit test to verify the validation

[msfluid-bot]

⯅ @fluid-example/bundle-size-tests: +116 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	445.22 KB	445.22 KB	■ No change
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	238.37 KB	238.37 KB	■ No change
loader.js	178.16 KB	178.25 KB	⯅ +83 Bytes
map.js	48.06 KB	48.06 KB	■ No change
matrix.js	141.84 KB	141.84 KB	■ No change
odspDriver.js	90.21 KB	90.24 KB	⯅ +33 Bytes
odspPrefetchSnapshot.js	41.75 KB	41.75 KB	■ No change
sharedString.js	162.68 KB	162.68 KB	■ No change
sharedTree2.js	266.3 KB	266.3 KB	■ No change
Total Size	1.72 MB	1.72 MB	⯅ +116 Bytes

---

Baseline commit: b856d87

Generated by 🚫 dangerJS against 0d41cd7