Fix prompt for using external metastore (#1668)

## Changes
A period and space were missing in the prompt for using external
metastore

### Functionality 

- [ ] added relevant user documentation
- [ ] added new CLI command
- [ ] modified existing command: `databricks labs ucx ...`
- [ ] added a new workflow
- [ ] modified existing workflow: `...`
- [ ] added a new table
- [ ] modified existing table: `...`

### Tests
<!-- How is this tested? Please see the checklist below and also
describe any other relevant tests -->

- [x] manually tested
- [ ] added unit tests
- [ ] added integration tests
- [ ] verified on staging environment (screenshot attached)

Author: JCZuurmond

src/databricks/labs/ucx/installer/policy.py

@@ -39,7 +39,7 @@ def create(self, inventory_database: str) -> tuple[str, str, dict, str | None]:
         instance_pool_id = self._get_instance_pool_id()
         policies_with_external_hms = list(self._get_cluster_policies_with_external_hive_metastores())
         if len(policies_with_external_hms) > 0 and self._prompts.confirm(
-            "We have identified one or more cluster policies set up for an external metastore"
+            "We have identified one or more cluster policies set up for an external metastore. "
             "Would you like to set UCX to connect to the external metastore?"
         ):
             logger.info("Setting up an external metastore")
@@ -50,7 +50,7 @@ def create(self, inventory_database: str) -> tuple[str, str, dict, str | None]:
         else:
             warehouse_config = self._get_warehouse_config_with_external_hive_metastore()
             if warehouse_config and self._prompts.confirm(
-                "We have identified the workspace warehouse is set up for an external metastore"
+                "We have identified the workspace warehouse is set up for an external metastore. "
                 "Would you like to set UCX to connect to the external metastore?"
             ):
                 logger.info("Setting up an external metastore")