bug: Close on overlay click -ModalRecordSelector

[FidalMathew]

Fixes #3207

This PR fixes the on-click overlay issue for ModalRecordSelector. The issue is resolved using appropriate z-index values for components.

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[FidalMathew]

@seancolsen The PR contains some local development changes, shall I remove them? The main changes include 2 files:

• mathesar_ui/src/systems/record-selector/ModalRecordSelector.svelte
• mathesar_ui/src/systems/record-selector/RecordSelectorWindow.svelte

I see that there's a linting error, it can be solved using the lint.sh command right?
Let me know if any changes are required. Thank you!

[seancolsen]

@FidalMathew yes, for this PR and for others in general: please make the diff as small as possible to fix the issue, and please ensure there are no linting errors.

[seancolsen]

Closed in favor of #3220