MM-54182 - add correct information to session table from mobile devices (#24353)

* MM-54182 - add correct information to session table from mobile devices

* improve comments around helper function

---------

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

server/channels/utils/utils_test.go

@@ -5,6 +5,7 @@ package utils
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -279,6 +280,32 @@ func TestRoundOffToZeroes(t *testing.T) {
 	}
 }
 
+func TestIsMobileRequest(t *testing.T) {
+	testCases := []struct {
+		userAgent string
+		expected  bool
+	}{
+		// Test cases with mobile devices
+		{"Mozilla/5.0 (iPhone; CPU iPhone OS 15_0 like Mac OS X)", true},
+		{"Mozilla/5.0 (Android 12; Mobile)", true},
+		{"Mozilla/5.0 (Linux; Android 12; Pixel 6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.9999.99 Mobile Safari/537.36", true},
+
+		// Test cases with NO mobile devices
+		{"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36", false},
+		{"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36", false},
+	}
+
+	for _, tc := range testCases {
+		req := httptest.NewRequest(http.MethodGet, "/", nil)
+		req.Header.Set("User-Agent", tc.userAgent)
+
+		result := IsMobileRequest(req)
+		if result != tc.expected {
+			t.Errorf("User-Agent: %s, expected: %v, got: %v", tc.userAgent, tc.expected, result)
+		}
+	}
+}
+
 func TestRoundOffToZeroesResolution(t *testing.T) {
 	messageGranularity := 3
 	storageGranularity := 8