Screen Coordinates Override, Move Stripping To Global Settings

[etienne-p]

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Purpose of this PR

Following up on #6597
According to the settings placement diagram,
Screen Coord Override shader stripping belongs to URP Global Settings.
We move it there from the URP asset.

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Testing status

Manually tested.

Comments To Testers/QA:

How to test: (@metalpat) build a cluster display project with stripping enabled, post effects should appear as unadapted to cluster display, normal screen space. Then build with stripping disabled, post effects should take cluster display in account. A Vignette effect with a ClusterRenderer using a TiledProjection with the stitcher activated is the most obvious way to check it out. Note that this is a URP feature and when we say "stripping enabled/disabled" we're specifically talking about the "Strip Screen Coord Override Variants" field added to URP Global Settings.

[github-actions]

Hi! This comment will help you figure out which jobs to run before merging your PR. The suggestions are dynamic based on what files you have changed.
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[github-actions]

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[wenzhang-unity]

LGTM