Bug Fix for unsafe_remove_check_constraint in certain Rails version

[imsurajmishra]

We identified that for certain rails version ( 6.1+, 7.0 ) , when we use symbol for constraint name, migration fails :

> -- remove_check_constraint("test_models", {:name=>:constraint_check_on_test_int_foo})
ArgumentError: Table 'test_models' has no check constraint for {:name=>:constraint_check_on_test_int_foo}

the bug is in this code path :
https://github.com/rails/rails/blob/16d8b82d5e2aca4780c5d10b1fe9a90b33a0e84e/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb#L1772-L1773

Note: this bug has been fixed in rails 7.1

This PR mainly overriding unsafe_remove_check_constraint method and converts name arg to name.to_s