configs: the stream9 image is "ready" for Mock bootstrap

Fixes: rpm-software-management#1442

behave/features/hermetic-build.feature

@@ -12,9 +12,6 @@ Feature: Mock 5.7+ supports hermetic builds
     @hermetic_build
     Scenario: Hermetic build against a DNF4 distribution
         Given an unique mock namespace
-        # Temporary image, until we resolve https://issues.redhat.com/browse/CS-2506
-        And next mock call uses --config-opts=bootstrap_image=quay.io/mock/behave-testing-c9s-bootstrap option
-        And next mock call uses --config-opts=bootstrap_image_ready=True option
         When deps for mock-test-bump-version-1-0.src.rpm are calculated against centos-stream+epel-9-x86_64
         And a local repository is created from lockfile
         And a hermetic build is retriggered with the lockfile and repository

mock-core-configs/etc/mock/templates/centos-stream-9.tpl

@@ -6,6 +6,7 @@ config_opts['extra_chroot_dirs'] = [ '/run/lock', ]
 config_opts['description'] = 'CentOS Stream 9'
 
 config_opts['bootstrap_image'] = 'quay.io/centos/centos:stream9'
+config_opts['bootstrap_image_ready'] = True
 
 config_opts['dnf.conf'] = """
 [main]

releng/release-notes-next/c9s-image-ready.config

@@ -0,0 +1,3 @@
+The centos-stream-9 (and transitively centos-stream+epel-9) configuration has
+been fixed to rely on "bootstrap image" readiness for Mock builds
+[issue#1442][].