Why:
* The default value of wgAutoCreateTempUser has not changed since
the decision to use a different prefix for temporary accounts
(T332805).
* The default needs to be updated to reduce the number of overrides
in operations/mediawiki-config and also to make the development
experience more consistent with what is happening on WMF
production.
What:
* Update the wgAutoCreateTempUser default in the following ways:
** Set expireAfterDays as 365
** Set notifyBeforeExpirationDays as 10
** Set genPattern and reservedPattern to '~$1'
** Set matchPattern to null, which will mean that the genPattern
is used as the value.
* Update RealTempUserConfig::getPlaceholderName to add the year to
the placeholder name so that if the match pattern includes the
first digit of the year, then the placeholder name still is
considered a valid temporary account username.
* Replace modifications of the wgAutoCreateTempUser config in
integration tests with a use of the TempUserTestTrait to make
the code cleaner and make it easier to find tests that relies on
the values in wgAutoCreateTempUser.
* Update multiple tests to handle the new defaults for the config.
Bug: T359335
Change-Id: Ifa5a0123cd915bdb7c87e473c51fb93321622f12
102424bfb3