MM-52173 Add setting to delay channel autocomplete (#22952)

* Add unit tests for ChannelMentionProvider.handleCompleteWord

* Add a minimum length before the ChannelMentionProvider triggers

* MM-52173 Move delayed autcomplete behind a setting

* Fix e2e test type check

* Update Textbox tests

* Add new setting to server telemetry

server/config/client.go

@@ -136,6 +136,7 @@ func GenerateClientConfig(c *model.Config, telemetryID string, license *model.Li
 	props["InsightsEnabled"] = strconv.FormatBool(c.FeatureFlags.InsightsEnabled)
 	props["PostPriority"] = strconv.FormatBool(*c.ServiceSettings.PostPriority)
 	props["AllowSyncedDrafts"] = strconv.FormatBool(*c.ServiceSettings.AllowSyncedDrafts)
+	props["DelayChannelAutocomplete"] = strconv.FormatBool(*c.ExperimentalSettings.DelayChannelAutocomplete)
 
 	if license != nil {
 		props["ExperimentalEnableAuthenticationTransfer"] = strconv.FormatBool(*c.ServiceSettings.ExperimentalEnableAuthenticationTransfer)

server/model/config.go

@@ -973,6 +973,7 @@ type ExperimentalSettings struct {
 	EnableAppBar                    *bool   `access:"experimental_features"`
 	PatchPluginsReactDOM            *bool   `access:"experimental_features"`
 	DisableRefetchingOnBrowserFocus *bool   `access:"experimental_features"`
+	DelayChannelAutocomplete        *bool   `access:"experimental_features"`
 }
 
 func (s *ExperimentalSettings) SetDefaults() {
@@ -1015,6 +1016,10 @@ func (s *ExperimentalSettings) SetDefaults() {
 	if s.DisableRefetchingOnBrowserFocus == nil {
 		s.DisableRefetchingOnBrowserFocus = NewBool(false)
 	}
+
+	if s.DelayChannelAutocomplete == nil {
+		s.DelayChannelAutocomplete = NewBool(false)
+	}
 }
 
 type AnalyticsSettings struct {

server/platform/services/telemetry/telemetry.go

@@ -760,6 +760,7 @@ func (ts *TelemetryService) trackConfig() {
 		"enable_app_bar":                      *cfg.ExperimentalSettings.EnableAppBar,
 		"patch_plugins_react_dom":             *cfg.ExperimentalSettings.PatchPluginsReactDOM,
 		"disable_refetching_on_browser_focus": *cfg.ExperimentalSettings.DisableRefetchingOnBrowserFocus,
+		"delay_channel_autocomplete":          *cfg.ExperimentalSettings.DelayChannelAutocomplete,
 	})
 
 	ts.SendTelemetry(TrackConfigAnalytics, map[string]any{