Update templates/install-wp-tests.sh

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: swissspidy

templates/install-wp-tests.sh

@@ -295,7 +295,7 @@ install_db() {
 	else
 		local DB_CLIENT='mysql'
 	fi
-	if [ $($DB_CLIENT --user="$DB_USER" --password="$DB_PASS"$EXTRA --execute='show databases;' | grep ^$DB_NAME$) ]
+	if $DB_CLIENT --user="$DB_USER" --password="$DB_PASS"$EXTRA --execute='show databases;' | grep -q "^$DB_NAME$";
 	then
 		echo -e "${YELLOW}Reinstalling will delete the existing test database ($DB_NAME)${RESET}"
 		read -p 'Are you sure you want to proceed? [y/N]: ' DELETE_EXISTING_DB