fix: Fix grants statements on materialized views

[AcidFlow]

resolves #1268

Problem

Granting privileges on materialized views was failing because the generated SQL statement used the relation type materialized_view as part of the query instead of materialized view (with a space).

Solution

This PR defines an override for this specific materialization in the and grant/revoke macros to fix the generated query.

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX

[kubikb]

Hello @AcidFlow @VersusFacit @colin-rogers-dbt , could you please take a look at this PR? This is an issue that requires a custom workaround from us. This PR has been open for some time and the fix here would resolve this persistent issue.

[AcidFlow]

Hello @AcidFlow @VersusFacit @colin-rogers-dbt , could you please take a look at this PR? This is an issue that requires a custom workaround from us. This PR has been open for some time and the fix here would resolve this persistent issue.

Hey @kubikb !

As a workaround if this PR does not get enough attention, what we did internally was to copy the two macros changed in this PR, to our dbt project macros directory. They will then take precedence over the one in the dbt-bigquery adapter and fix the issue until a fix is available upstream.

[colin-rogers-dbt]

Apologies for the delay here, we do want to get this merged in but will likely look to extend our functional tests to cover this case here