CMCL-1533: address UX comments from design team

[glabute]

Purpose of this PR

After a demo of CM 3, the design team (Christine Rivard) raised some concerns about UX idiosyncrasies.

Met with Julien Didierjean to work out a plan and settled on these interventions:

• CinemachineCamera inspector: change the text of the Procedural Motion header to something that better suggests that the dropdowns are helpers to manage the sibling components. We will use Set Procedural Components
• Add visible text to the blank dropdown next to the lens FOV field. Text will say Palette. Update the tooltip accordingly, eliminating use of the word "preset" which can be confused with component presets.
• Add a clarifying helpbox to procedural component inspectors in the case where multiple components are added for the same pipeline slot (issue came to light in the demo). Helpbox will indicate that the extra components are redundant and will be ignored.

Testing status

• Added an automated test
• Passed all automated tests
• Manually tested

Documentation status

• Updated CHANGELOG
• Updated README (if applicable)
• Commented all public classes, properties, and methods
• Updated user documentation

Technical risk

low