Fix SystemStackError when extending ActiveRecord::SchemaDumper#initialize with Module#prepend

[willnet]

Same issue as #216.

strong_migrations overrides ActiveRecord::SchemaDumper#initialize using Module#prepend, which caused a SystemStackError when used with activerecord-multi-tenant.

https://github.com/ankane/strong_migrations/blob/8e9baaa05c35fc9fdf206160c00b309c6e3a8bb6/lib/strong_migrations/schema_dumper.rb#L3-L7

Fix the issue by changing the alias in activerecord-multi-tenant to use prepend.

[willnet]

@microsoft-github-policy-service agree