[Design] SSBC: Add toggles for `AllowUnsupported` and `AllowIgnored` on execution

Created by: courier-new

Design for https://github.com/sourcegraph/sourcegraph/issues/34248.

Expand the execution options menu to include toggles for the AllowUnsupported and AllowIgnored flags:

If AllowUnsupported is true, repos on unsupported code hosts will still be executed on, but resulting changesets in these repos cannot be automatically published by Sourcegraph.

If AllowIgnored is true, repos with a .batchignore file will still be executed on.

Both of these options will be default false.