1. remove `TEST_CONFLICTING_PATCHES_WITH_GIT_APPLY`
* it defaults to false and is unlikely to be useful for most users (see
#22130)
* with new git versions (>= 2.40), "merge-tree" is used,
"checkConflictsByTmpRepo" isn't called, the option does nothing.
2. fix fragile `db.Cell2Int64` (new: `CellToInt`)
3. allow more routes in maintenance mode (e.g.: captcha)
4. fix MockLocale html escaping to make it have the same behavior as
production locale
The banner allows site operators to communicate important announcements
(e.g., maintenance windows, policy updates, service notices) directly
within the UI.
The maintenance mode only allows admin to access the web UI.
* Fix#2345
* Fix#9618
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
