Only pause plugins/themes for persistent errors

[schlessera]

To avoid pausing plugins/themes through the fatal error protection because of random one-off errors, we should do a redirect first and see whether the error persists. If not, there's no need to pause the plugin/theme, it was just a temporary issue.

This ties into #45940, as it will further reduce the amount of pausing that we do.

[schlessera]

This first patch changes the 'error' array that we store into a 'record' array that contains both the 'error' and a 'count'.

There's a define WP_FATAL_ERROR_PROTECTION_REDIRECT_THRESHOLD that defaults to 2.

A plugin/theme is only paused if the consecutive count of the same error happening after redirects reaches said threshold.

To discuss:

• Do we need such a constant?
• Do we need to count the number of redirects and make sure we're not doing an infinite loop?

[flixos90]

This ticket is based on the old fatal error recovery mode implementation and will be covered as part of #46130.