fix: Plugin "Check it!" button fails silently with nonce error #893

[kmfoysal06]

What?

Closes #893

The changes in this PR are to add a custom error notice in the UI instead of showing the error in the console when an error occurs in the catch block.

Why?

The issue mentioned above shows how, after some time, when the nonce gets expired, the check plugin button does not work and shows an invalid nonce message in the console. So, the solution is either to tell the user about the nonce expiration on the client side visually or reload the page automatically. As reloading the page won't be a consistent solution, I decided to show an admin error notice informing the user that the nonce has expired.

How?

My suggested solution is to show the error message from the server side directly as an admin error notice so the user can understand why the plugin check is failing.

Testing Instructions

1. Open 'Plugin Check' from Dashboard > Tools.
2. Open Browser DevTools and paste PLUGIN_CHECK.nonce = 'gg' and press Enter to make the nonce invalid.
3. Select any plugin and click the "Check It!" button to check the plugin.
4. The admin error notice will be visible with the error message from the server side.

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• This PR was created without the help of AI tools
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If AI tools were used, please describe how they were used:
AI tools used in this PR only to modify the PR message to ensure no grammar mistake included in the message.

Before	After

Unlinked contributors: tamimhasan19702, rtpHarry.

Co-authored-by: kmfoysal06 kmfoysal06@git.wordpress.org
Co-authored-by: iyut aralle@git.wordpress.org

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