Fix env support in prepare runner

This change corrects prepare runner playbook being not aware of running environment when we use input environment selector.

Author: darmach

roles/github/templates/prepare-runner.yml.j2

@@ -1,3 +1,6 @@
+<%- if github_environment_selector == 'input' and (github_registry.share | default(github_default_registry.share)) is false -%>
+<%- set github_runs_on = github_runs_on + ['${{ matrix.environment }}'] -%>
+<%- endif -%>
 name: %% format_file_name(workflow.file_name, is_title=true) %%
 
 on: