fix(ci): install firebird extension from PECL for fbird_* functions

Author: mariuz

.github/docker/php-apache-firebird/Dockerfile

@@ -1,3 +1,6 @@
 FROM php:8.1-apache
 RUN apt-get update && apt-get install -y firebird-dev && \
-    docker-php-ext-install pdo_firebird && a2enmod rewrite
+    pecl install firebird && \
+    docker-php-ext-install pdo_firebird && \
+    docker-php-ext-enable firebird && \
+    a2enmod rewrite