Revert "Add AVIF support for gd"

This reverts commit f4b26ea.

Author: patrikjuvonen

Dockerfile

@@ -126,7 +126,6 @@ Pin-Priority: 1001\n" > /etc/apt/preferences.d/nginx; \
 	# Install build dependencies to compile PHP extensions
 	apt-get install -y --no-install-recommends \
 		# gd
-		libavif-dev \
 		libfreetype6-dev \
 		libjpeg-dev \
 		libpng-dev \
@@ -145,7 +144,6 @@ Pin-Priority: 1001\n" > /etc/apt/preferences.d/nginx; \
 	\
 	# Configure PHP GD extension
 	docker-php-ext-configure gd \
-		--with-avif \
 		--with-freetype \
 		--with-jpeg \
 		--with-webp \