refactor(geospatial): move geospatial tests to backend test suite

[cpcloud]

We have a number of backends that can support geospatial, and at least 3 that currently do. We should avoid adding anymore geospatial API tests that are backend specific and move any that are to the backend test suite.

Support backends

• duckdb
• postgres
• bigquery

Upstream support but no Ibis support

• mysql
• mssql
• snowflake
• trino
• clickhouse (these don't follow the postgis API unfortunately and in general the support is extremely limited)