Auth: Update okta docs - `use_pkce = true` by default. #73754 (#73756)

Signed-off-by: junya koyama <arukiidou@yahoo.co.jp>

docs/sources/setup-grafana/configure-security/configure-authentication/okta/index.md

@@ -84,7 +84,7 @@ The following table outlines the various Okta OAuth2 configuration options. You
 | `skip_org_role_sync`    | No       | Set to `true` to stop automatically syncing user roles. This will allow you to set organization roles for your users from within Grafana manually.                                                                                                                                                                                                                                                                                                                                                                             | `false`                       |
 | `allowed_groups`        | No       | List of comma- or space-separated groups. The user should be a member of at least one group to log in.                                                                                                                                                                                                                                                                                                                                                                                                                         |                               |
 | `allowed_domains`       | No       | List comma- or space-separated domains. The user should belong to at least one domain to log in.                                                                                                                                                                                                                                                                                                                                                                                                                               |                               |
-| `use_pkce`              | No       | Set to `true` to use [Proof Key for Code Exchange (PKCE)](https://datatracker.ietf.org/doc/html/rfc7636). Grafana uses the SHA256 based `S256` challenge method and a 128 bytes (base64url encoded) code verifier.                                                                                                                                                                                                                                                                                                             | `false`                       |
+| `use_pkce`              | No       | Set to `true` to use [Proof Key for Code Exchange (PKCE)](https://datatracker.ietf.org/doc/html/rfc7636). Grafana uses the SHA256 based `S256` challenge method and a 128 bytes (base64url encoded) code verifier.                                                                                                                                                                                                                                                                                                             | `true`                        |
 | `use_refresh_token`     | No       | Set to `true` to use refresh token and check access token expiration. The `accessTokenExpirationCheck` feature toggle should also be enabled to use refresh token.                                                                                                                                                                                                                                                                                                                                                             | `false`                       |
 
 ### Configure a refresh token