Add APIs to omit module prefix separator

[jackkoenig]

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Type of Improvement

• Feature (or new API)

Desired Merge Strategy

• Squash

Release Notes

• withModulePrefix now optionally takes a 2nd parameter includeSeparator (passing false will omit separator).
• Overriding localModulePrefixUseSeparator in a Module to false will omit separator for local prefix applied by overriding localModulePrefix in that Module.

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[jackkoenig]

I removed this API because it's complicated by the separator being optional and it isn't currently used (it was used internally in Instantiate but its use would technically be wrong with separator now being optional).

[mwachs5]

approving, though we could add one more test case for showing the sep override is only for one layer of hierarchy