Use custom actions for rendering admin pages

[christianwach]

Overview

Fixes this issue on Lab.

Before

PHP warnings from plugins such as:

PHP Warning:  Attempt to read property "ID" on null in /path/to/httpdocs/wp-content/plugins/acf-extended/includes/module-post.php on line 39

After

No PHP warnings.

[kcristiano]

@christianwach It read like a good change to me, but all PRs are failing test E2E_Core_PathUrlTest/testGetUrl_WpAdmin/ here . I am thinking we may need to ignore that one.

@seamuslee001 @totten any input? I tried to fix the test but it passes sporadically on my buildkit local install

[christianwach]

Is it this test that's failing? I don't have phpunit here, but looking at those assertEquals() statements, they shouldn't be failing given the output of cv('url civicrm/contribute?reset=1') on my machine. Weird.

[christianwach]

@kcristiano Thanks for reviewing 👍

[kcristiano]

test this please

[kcristiano]

Re-tested against master. Code is good and r-run is successful.

Test fail is unrelated and all tests pass locally.