MM-64330 - filter abac users in channel invite (#31219)

* MM-64330 - filter abac users in channel invite

* implement cursor functionality for abac user filtering

* remove unnecessary comments

* refactor the backend implementation simplifying the functions

* refactor api to use opts as parameters, rename function

* add missing translation

* remove unnecesary test code

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Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/model/user.go

@@ -243,6 +243,19 @@ type ViewUsersRestrictions struct {
 	Channels []string
 }
 
+//msgp:ignore GetUsersNotInChannelOptions
+type GetUsersNotInChannelOptions struct {
+	TeamID string `json:"team_id"`
+	// Page-based pagination (used for non-ABAC channels)
+	// This will be discarded if the channel has an ABAC policy and CursorID will be used.
+	Page  int `json:"page"`
+	Limit int `json:"limit"`
+	// Cursor-based pagination (used for ABAC channels)
+	// If CursorID is empty for ABAC channels, it will start from the beginning
+	CursorID string `json:"cursor_id"`
+	Etag     string `json:"etag"`
+}
+
 func (r *ViewUsersRestrictions) Hash() string {
 	if r == nil {
 		return ""