fix(tree): insert* and move* should accept proxy API types

[DLehenbauer]

SharedListNode.insert*() needed adjustment to accept the new factory-created content.
SharedListNode.move*() needed adjustment to accept to accept a SharedListNode as source.

Testing also uncovered and fixed a couple of minor bugs in the move implementation:

• Use 'boxedAt()' when validating that the items in the source list comply with the destination type.
• The adjustment of the destination index wasn't quite right.

[msfluid-bot]

⯅ @fluid-example/bundle-size-tests: +311 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	445.96 KB	445.96 KB	■ No change
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	239.05 KB	239.05 KB	■ No change
loader.js	178.73 KB	178.73 KB	■ No change
map.js	48.06 KB	48.06 KB	■ No change
matrix.js	141.84 KB	141.84 KB	■ No change
odspDriver.js	90.27 KB	90.27 KB	■ No change
odspPrefetchSnapshot.js	41.9 KB	41.9 KB	■ No change
sharedString.js	162.75 KB	162.75 KB	■ No change
sharedTree2.js	262.91 KB	263.21 KB	⯅ +311 Bytes
Total Size	1.72 MB	1.72 MB	⯅ +311 Bytes

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Baseline commit: 0d1436b

Generated by 🚫 dangerJS against 541b568

[noencke]

Awesome!

[noencke]

Suggested change

	? sourceStart // distination overlaps with source range -> slide to left
	? sourceStart // destination overlaps with source range -> slide to left

This typo made me realize that while "src" and "dest" are opposites, so are "src" and "dist".