Fix DBConsistency checks on MSSQL (#23132)

Fix DBConsistency checks on MSSQL (#23132)

Unfortunately xorm's `builder.Select(...).From(...)` does not escape the
table names. This is mostly not a problem but is a problem with the
`user` table.

This PR simply escapes the user table. No other uses of `From("user")`
where found in the codebase so I think this should be all that is
needed.

Fix #23064

Signed-off-by: Andrew Thornton <art27@cantab.net>