spelling: strings (#19542)

Co-authored-by: Josh Soref <jsoref@users.noreply.github.com>
Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

app/plugin_api_test.go

@@ -1850,7 +1850,7 @@ func TestPluginAPISearchPostsInTeamByUser(t *testing.T) {
 	api := th.SetupPluginAPI()
 
 	basicPostText := &th.BasicPost.Message
-	unknwonTerm := "Unknown Message"
+	unknownTerm := "Unknown Message"
 
 	testCases := []struct {
 		description      string
@@ -1870,7 +1870,7 @@ func TestPluginAPISearchPostsInTeamByUser(t *testing.T) {
 			"doesn't match any posts",
 			th.BasicTeam.Id,
 			th.BasicUser.Id,
-			model.SearchParameter{Terms: &unknwonTerm},
+			model.SearchParameter{Terms: &unknownTerm},
 			0,
 		},
 		{