Why:
Sometimes, it is necessary to have different behavior
for newly registered and existing users. For example,
this happens in the Echo or GrowthExperiments extensions.
As of now, this behavior is implemented by inserting
user_properties rows in onLocalUserCreated.
Over time, this results in a singificant amount of rows
inserted, which contributes to the user_properties table bloat,
which is already overly large (cf. T54777). This patch makes it
possible to remove such rows by supporting conditional defaults
for user properties.
What:
Add support for conditional defaults of user properties. This can be
configured via `ConditionalUserOptions` config option.
Bug: T321527
Change-Id: I1549c3137e66801c85e03e46427e27da333d68e2
6c8b696020