Warn when pages multiple deployments is disabled

What does this MR do and why?

Warn when pages multiple deployments is disabled. Before, this was just ignoring the field without letting the user know.

Related to: #458018 (closed)

Changelog: added

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Screenshots or screen recordings

Screen_Recording_2024-04-29_at_18.51.14

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Screen_Recording_2024-04-24_at_22.37.08

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