Add ability to set multiple redirect URIs in OAuth application UI (#25072)

OAuth applications can already have multiple redirect URIs if
created/edited over API.

This change allows for setting multiple redirect URIs through the UI as
a comma-separated list (e. g.
`https://example.org/redirect,https://redirect.example.org`)

<details>
<summary>Screenshots</summary>

![Bildschirmfoto vom 2023-06-04
17-14-40](2206dc32-e7e4-4953-9ecb-e098890b3f54)
![Bildschirmfoto vom 2023-06-04
17-14-50](cd97c73c-9310-44ee-a83a-b927a1ef94da)

</details>

Closes #25068

services/forms/user_form.go

@@ -398,7 +398,7 @@ func (f *NewAccessTokenForm) GetScope() (auth_model.AccessTokenScope, error) {
 // EditOAuth2ApplicationForm form for editing oauth2 applications
 type EditOAuth2ApplicationForm struct {
 	Name               string `binding:"Required;MaxSize(255)" form:"application_name"`
-	RedirectURI        string `binding:"Required" form:"redirect_uri"`
+	RedirectURIs       string `binding:"Required" form:"redirect_uris"`
 	ConfidentialClient bool   `form:"confidential_client"`
 }