Adding color4f(array) support to the _FactoryMap

[robpieke]

Description of Change(s)

Copy-paste to add Color4f/Color4fArray to the _FactoryMap of convertible types to support shader nodes with color4f parameters.

Fixes Issue(s)

Fixes #3298

• [X] I have verified that all unit tests pass with the proposed changes
• [X] I have submitted a signed Contributor License Agreement

[jesschimein]

Filed as internal issue #USD-10150

[jesschimein]

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