[Fix] Increase databricks_library installation timeout from 15m to 30m (#4479)

## Changes
Currently, `databricks_library` waits for 15m for libraries to install.
We received a report that this was a bit too short for some use cases.
For now, I'll bump this up to 30m to mitigate the issue faced by this
customer.

The long-term plan to fix this should be based on adopting
https://developer.hashicorp.com/terraform/plugin/framework/resources/timeouts
in our provider.

## Tests

I did not do any tests for this change.

Author: mgyucht

NEXT_CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New Features and Improvements
 
  * Support updating `options` in `databricks_catalog` ([#4476](https://github.com/databricks/terraform-provider-databricks/pull/4476)).
+ * Increase `databricks_library` timeout from 15m to 30m.
 
 ### Bug Fixes
 

internal/providers/pluginfw/products/library/resource_library.go

@@ -29,7 +29,7 @@ import (
 )
 
 const resourceName = "library"
-const libraryDefaultInstallationTimeout = 15 * time.Minute
+const libraryDefaultInstallationTimeout = 30 * time.Minute
 
 var _ resource.ResourceWithConfigure = &LibraryResource{}