[Doc] Use correct names for isolation mode for storage credentials and external locations (#3804)

## Changes
<!-- Summary of your changes that are easy to understand -->

Fixes #3728

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

- [ ] `make test` run locally
- [x] relevant change in `docs/` folder
- [ ] covered with integration tests in `internal/acceptance`
- [ ] relevant acceptance tests are passing
- [ ] using Go SDK

Author: alexott

docs/resources/external_location.md

@@ -129,7 +129,7 @@ The following arguments are required:
 - `force_update` - (Optional) Update external location regardless of its dependents.
 - `access_point` - (Optional) The ARN of the s3 access point to use with the external location (AWS).
 - `encryption_details` - (Optional) The options for Server-Side Encryption to be used by each Databricks s3 client when connecting to S3 cloud storage (AWS).
-- `isolation_mode` - (Optional) Whether the external location is accessible from all workspaces or a specific set of workspaces. Can be `ISOLATED` or `OPEN`. Setting the external location to `ISOLATED` will automatically allow access from the current workspace.
+- `isolation_mode` - (Optional) Whether the external location is accessible from all workspaces or a specific set of workspaces. Can be `ISOLATION_MODE_ISOLATED` or `ISOLATION_MODE_OPEN`. Setting the external location to `ISOLATION_MODE_ISOLATED` will automatically allow access from the current workspace.
 
 ## Attribute Reference
 

docs/resources/storage_credential.md

@@ -80,7 +80,7 @@ The following arguments are required:
 - `skip_validation` - (Optional) Suppress validation errors if any & force save the storage credential.
 - `force_destroy` - (Optional) Delete storage credential regardless of its dependencies.
 - `force_update` - (Optional) Update storage credential regardless of its dependents.
-- `isolation_mode` - (Optional) Whether the storage credential is accessible from all workspaces or a specific set of workspaces. Can be `ISOLATED` or `OPEN`. Setting the credential to `ISOLATED` will automatically allow access from the current workspace.
+- `isolation_mode` - (Optional) Whether the storage credential is accessible from all workspaces or a specific set of workspaces. Can be `ISOLATION_MODE_ISOLATED` or `ISOLATION_MODE_OPEN`. Setting the credential to `ISOLATION_MODE_ISOLATED` will automatically allow access from the current workspace.
 
 `aws_iam_role` optional configuration block for credential details for AWS: