fix: avoid invalid condition reasons

[Diaphteiros]

What this PR does / why we need it:
We use the k8s default Condition type, which not only requires a non-empty Reason, but also validates it against a regex. To avoid issues, the ConditionUpdater just added a dummy reason if it was empty, for which it used the condition's Type. The regex for type and reason differ, though: type allows . but not :, while for the reason, it is the other way around.

This PR replaces . with : when using the type default the condition reason.

Which issue(s) this PR fixes:
Required for openmcp-project/openmcp-operator#115
(not a hard requirement, though, there is a workaround in place)

Special notes for your reviewer:

Release note:

The condition updater would produce an invalid dummy reason for a condition if that condition's type contained a `.`, because this is not an allowed character in the condition's reason. This is now avoided by replacing `.` with `:` when using the condition's type to construct a dummy reason.