perf: refactor PluginConnectionResolver to only fetch plugins once

[justlevine]

What does this implement/fix? Explain your changes.

This PR refactors our PluginConnectionResolver class to use a DRY ::get_all_plugins() method for building the list of available plugins.
This list is then stored in a class property, so the fetching, filtering, etc only occur once.

Does this close any currently open issues?

Any relevant logs, error output, GraphiQL screenshots, etc?

Part of #2749

Any other comments?

This PR is based on #3082 , which should be merged first.

Where has this been tested?

Operating System: Ubuntu 20.04 (wsl2 + devilbox + php 8.1.15)

WordPress Version: 6.4.3

[justlevine]

Ps @jasonbahl it might be easier for you to review/merge #3082 first, (PRs based on it, should auto-update the branch to develop) instead of merging the dependent PRs into #3082.

From my side: I don't know your availability for reviewing them all, but assuming it's a multi-day process, then merging the parent PRs before the dependents would also let me continue backporting more things while decreasing the risk of merge conflicts.

Either way

[jasonbahl]

This one didn't look like it had any direct connection to the others and could be merged as-is.

The others did seem to have a lot more correlation.

[justlevine]

@jasonbahl this was merged into #3082 , not into #3097 . We probably should amend the release notes.

[jasonbahl]

@justlevine ooph. Good call. Will update. Thanks. Just got the test results back and this was another case of the "moving too fasts"

[jasonbahl]

@justlevine edited the release notes: https://github.com/wp-graphql/wp-graphql/releases/tag/v1.23.0