coverage: Always process coverage, even if tests fail (#40167)

First, for projects that have both JS and PHP tests or multiple suites
of tests, run all the tests for coverage even if one fails. Mostly this
means using the `concurrently` package, since that's a very easy way to
run both and collect the exit statuses.

Then, in the workflow itself, add `always()` to the `if` on the step for
processing coverage reports so it runs even if the tests failed to
process whatever data is available.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/11842463094

Upstream-Ref: Automattic/jetpack@bbb0564

vendor/automattic/jetpack-assets/composer.json

@@ -34,10 +34,7 @@
 		"phpunit": [
 			"./vendor/phpunit/phpunit/phpunit --colors=always"
 		],
-		"test-coverage": [
-			"php -dpcov.directory=. ./vendor/bin/phpunit --coverage-php \"$COVERAGE_DIR/php.cov\"",
-			"pnpm run test-coverage"
-		],
+		"test-coverage": "pnpm concurrently --names php,js 'php -dpcov.directory=. ./vendor/bin/phpunit --coverage-php \"$COVERAGE_DIR/php.cov\"' 'pnpm:test-coverage'",
 		"test-js": [
 			"pnpm run test"
 		],

vendor/automattic/jetpack-assets/package.json

@@ -18,6 +18,7 @@
 	"devDependencies": {
 		"@automattic/jetpack-webpack-config": "workspace:*",
 		"@wordpress/browserslist-config": "6.11.0",
+		"concurrently": "7.6.0",
 		"jest": "29.7.0",
 		"md5-es": "1.8.2",
 		"webpack": "5.94.0",