fix: automatically link user without prompt (#8487)

# Which Problems Are Solved

There were UX issue with the autolinking prompt page and users were not
able to link their account or would not understand what to do. Since the
trust to the IdP is already bound by the configuration, the user can
directly be linked without any user input.

# How the Problems Are Solved

- remove the prompt page and directly link the user if possible
- remove corresponding customization texts from the API and Console

# Additional Changes

None

# Additional Context

- relates to https://github.com/zitadel/zitadel/issues/7977
- discussed with customers
- created as a `fix` to be able to backport

---------

Co-authored-by: Max Peintner <max@caos.ch>

internal/domain/custom_login_text.go

@@ -265,12 +265,6 @@ const (
 	LoginKeyRegisterOrgSaveButtonText       = LoginKeyRegistrationOrg + "SaveButtonText"
 	LoginKeyRegisterOrgBackButtonText       = LoginKeyRegistrationOrg + "BackButtonText"
 
-	LoginKeyLinkingUserPrompt                = "LinkingUserPrompt."
-	LoginKeyLinkingUserPromptTitle           = LoginKeyLinkingUserPrompt + "Title"
-	LoginKeyLinkingUserPromptDescription     = LoginKeyLinkingUserPrompt + "Description"
-	LoginKeyLinkingUserPromptLinkButtonText  = LoginKeyLinkingUserPrompt + "LinkButtonText"
-	LoginKeyLinkingUserPromptOtherButtonText = LoginKeyLinkingUserPrompt + "OtherButtonText"
-
 	LoginKeyLinkingUserDone                 = "LinkingUsersDone."
 	LoginKeyLinkingUserDoneTitle            = LoginKeyLinkingUserDone + "Title"
 	LoginKeyLinkingUserDoneDescription      = LoginKeyLinkingUserDone + "Description"
@@ -343,7 +337,6 @@ type CustomLoginText struct {
 	RegistrationUser                 RegistrationUserScreenText
 	ExternalRegistrationUserOverview ExternalRegistrationUserOverviewScreenText
 	RegistrationOrg                  RegistrationOrgScreenText
-	LinkingUserPrompt                LinkingUserPromptScreenText
 	LinkingUsersDone                 LinkingUserDoneScreenText
 	ExternalNotFound                 ExternalUserNotFoundScreenText
 	LoginSuccess                     SuccessLoginScreenText
@@ -616,13 +609,6 @@ type RegistrationOrgScreenText struct {
 	SaveButtonText       string
 }
 
-type LinkingUserPromptScreenText struct {
-	Title           string
-	Description     string
-	LinkButtonText  string
-	OtherButtonText string
-}
-
 type LinkingUserDoneScreenText struct {
 	Title            string
 	Description      string