Revert "Workaround imagick not compiling in actions"

This reverts commit cb345e9.

Author: TRowbotham

.github/workflows/tests.yml

@@ -46,7 +46,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php }}
-          extensions: mbstring, opcache, pcre, gmp, :imagick
+          extensions: mbstring, opcache, pcre, gmp
           ini-values: zend.assertions=1, opcache.enable_cli=1, opcache.memory_consumption=256, opcache.jit=${{ matrix.php-jit }}, opcache.jit_buffer_size=256M
           coverage: none
         env: