Allow extending configurable propeties with non-configurable properties

Sometimes modules add arch-variant properties in load hooks, to disable
modules by default on certain platforms for example. When changing the
property to a Configurable property, these load hooks would also need
to be changed in order to have a matching type for
ExtendMatchingProperties.

Since this can be kindof a pain to address everywhere, for now,
special case the extension functions to promote non-configurable
properties to configurable ones. We can remove this later when
everything switches to configurable properties.

Bug: 323382414
Test: go tests
Change-Id: Iac96587dbd60ccdd6aa667dd69a71ad252abe589
3 files changed