Add admin notice warning when installed plugins are not tested with the current WordPress version

[AKSHAT2802]

Trac ticket: https://core.trac.wordpress.org/ticket/40804

This PR introduces a new inline admin warning in the Plugins > Installed Plugins screen when a plugin’s "Tested up to" version (retrieved via plugins_api()) is lower than the current installed WordPress version.

The goal is to improve plugin maintenance visibility and help site owners quickly identify plugins that may no longer be actively tested or maintained without requiring them to open the plugin details modal.

This enhancement aligns with similar UX patterns used in the Plugin Directory, where outdated testing information already triggers caution labels.

Behavior

• If the installed plugin has not been tested up to the current WordPress version, a dismissible inline warning is shown below the plugin row.
• The notice includes the current WordPress version and the last tested version returned from the API.
• If the user has capability install_plugins, a "View details" link is appended to allow quick access to the plugin modal.

Example message:

This plugin has not been tested with your current version of WordPress (6.8). It may still work, but consider checking for an update or contacting the plugin author. Last tested with WordPress 6.6.

New Filters Introduced

1. show_plugin_compatibility_warning
   Allows controlling whether the warning should appear.

apply_filters( 'show_plugin_compatibility_warning', $show_compat_warning, $plugin_file, $plugin_data, $tested_wp, $wp_version );

2. plugin_compatibility_warning_message
   Allows customizing the text of the warning.

apply_filters( 'plugin_compatibility_warning_message', $compat_message, $plugin_file, $plugin_data, $tested_wp, $wp_version );

Testing Instructions

• Install any plugin with a "Tested up to" value lower than the current WordPress install.

• Visit Plugins → Installed Plugins.

• Confirm:
  -- A warning row appears under the plugin.
  --The text correctly inserts both version values.
  -- The link opens the plugin details thickbox modal (if capabilities allow).

[github-actions]

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Test this pull request with WordPress Playground.

[github-actions]

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Props akshat2802, westonruter.

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