This commit fixes a regression in property placeholder resolution where
the original key was no longer considered for an exact match before
processing the placeholder itself.
By default, property resolution uses ':' as the separator between the
key and the fallback value.
Consider a request to resolve ${prefix://service}. Previously,
placeholder resolution would first attempt to resolve the raw text, that
is 'prefix://service', before attempting to resolve the 'prefix' key and
then use '//service' if the key did not resolve.
This commit restores that behaviour purely for backward compatible
reason.
Closes gh-34124
5ce5647d09