fix(schematics): rewrite projectFromRc and add spec file

[nontangent]

Checklist

• Issue number for this PR: Code in schematics/deploy/builder.ts is preventing the usage of any non-default firebaseProject and firebaseHostingSite values #3077 (required)
• Docs included?: no
• Test units included?: yes
• In a clean directory, yarn install, yarn test run successfully? (yes/no; required)

Description

Fix #3077 and add unit tests.

Code sample

No API changes.

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[nontangent]

I've just signed CLA.

[davideast]

@nontangent Thank you so much for this contribution and I apologize for how late it took us to get to it. I'll need to test through one a bit thoroughly myself so hang tight.

[arlopezg]

I think this would fix #3309