## Changes
`TestAccFilerWorkspaceFilesExtensionsErrorsOnDupName` recently started
failing in our nightlies because the upstream `import` API was changed
to [prohibit conflicting file
paths](https://docs.databricks.com/en/release-notes/product/2024/august.html#files-can-no-longer-have-identical-names-in-workspace-folders).
Because existing conflicting file paths can still be grandfathered in,
we need to retain coverage for the test. To do this, this PR:
1. Removes the failing
`TestAccFilerWorkspaceFilesExtensionsErrorsOnDupName`
2. Add an equivalent unit test with the `list` and `get-status` API
calls mocked.
shreyas-goenka