Allow project import even when `shared_runners_enabled` conflicts

What does this MR do and why?

• modifies the imported project's value of shared_runners_enabled to be false if it conflicts with the group's shared_runners_setting setting of disabled_and_unoverridable
  • this can happen when a project is imported from a group where this setting was allowed to be true, but the target group's setting is different(disabled_and_unoverridable is set), therefore we have to honor that when we move the project to this new group.
• this fixes the hard stop bug we are encountering as described in #276930 (closed)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #276930 (closed)