chore: Adjust authentication policy

[sfc-gh-jcieslak]

Changes

• Addressed comments from https://github.com/Snowflake-Labs/terraform-provider-snowflake/pull/2937
• Fixed failing tests caused by this change
• Changed and added multiple tests connected to auth policies
• Adjusted a few parts of the SDK implementation (using enums where possible, added a few missing parts, etc.)

TODO

• Mention in https://github.com/Snowflake-Labs/terraform-provider-snowflake/issues/2880 that the SDK for Auth Policies is ready

[github-actions[bot]]

Integration tests failure for 25924bed8692ac8da0a3d211d49aa19a35a15c0f

[github-actions[bot]]

Integration tests failure for 34bff3666d447bad2520963746f173b786e8bfb9

[github-actions[bot]]

Integration tests failure for ac66d8177a8e2e2ab968c433349b1065985b0ca1

[github-actions[bot]]

Integration tests failure for 0be9f62f46ad1f35772be51a7bae78d2641d504f