bp_is_current_component() fallback $page check breaks on certain custom components

[boonebgorges]

When combining custom post type archives with custom BuddyPress components, the page template fallback checks in bp_is_current_component() can fail improperly. There, we get the current "page" with get_queried_object(). But in the case of an archive, the return value will not have an ID. Thus, we should check for the existence of the ID property before looking for a corresponding page template.

[boonebgorges]

In 8611:

More conservative page_template checks in bp_is_current_component()

The page_template checks in bp_is_current_component() should not go through if
the currently queried object is not a single page (ie when a plugin is forcing
it to be a CPT archive). So we check for the presence of the ID property
before attempting to use it.

Fixes #5751