--filters feature not working on MySQL.

[claudenm]

Similar to #760, when running a validation with a MySQL source we get:

No translation rule for <class 'third_party.ibis.ibis_addon.operations.RawSQL'>

The validation was:

data-validation -v validate row  --source-conn mysql -tc bq --tables-list mysql.redacted=bq.redacted --comparison-fields=field1,field2,field3 --primary-keys=id --filters='id>1'

A working validation, omitting the filter is:

data-validation -v validate row  --source-conn mysql -tc bq --tables-list mysql.redacted=bq.redacted --comparison-fields=field1,field2,field3 --primary-keys=id -rr

We'll need to validate billion row tables, so would appreciate this being patched.

[kanhaPrayas]

#812