[mob][photos] video streaming description spacing and alignment (#6992)

## Summary
- Split videoStreamingDescription into separate line1/line2 localization
keys
- Remove TextAlign.justify from enabled state to fix awkward word
spacing
- Standardize text rendering between enabled and disabled states
- Both states now display description consistently without spacing
issues

## Test plan
- [x] Verify enabled state displays as single line without spacing
issues
- [x] Verify disabled state shows proper line breaks in onboarding
- [x] Confirm localization keys generate correctly
- [x] Run dart format and dart analyze (no issues)

Fixes video streaming settings page text display inconsistencies.

mobile/apps/photos/lib/l10n/intl_en.arb

@@ -1831,7 +1831,8 @@
   "videosProcessed": "Videos processed",
   "totalVideos": "Total videos",
   "skippedVideos": "Skipped videos",
-  "videoStreamingDescription": "Play videos instantly on any device.\nEnable to process video streams on this device.",
+  "videoStreamingDescriptionLine1": "Play videos instantly on any device.",
+  "videoStreamingDescriptionLine2": "Enable to process video streams on this device.",
   "videoStreamingNote": "Only videos from last 60 days and under 1 minute are processed on this device. For older/longer videos, enable streaming in the desktop app.",
   "createStream": "Create stream",
   "recreateStream": "Recreate stream",

mobile/apps/photos/lib/ui/settings/streaming/video_streaming_settings_page.dart

@@ -100,7 +100,12 @@ class _VideoStreamingSettingsPageState
                             children: [
                               TextSpan(
                                 text: AppLocalizations.of(context)
-                                    .videoStreamingDescription,
+                                    .videoStreamingDescriptionLine1,
+                              ),
+                              const TextSpan(text: " "),
+                              TextSpan(
+                                text: AppLocalizations.of(context)
+                                    .videoStreamingDescriptionLine2,
                               ),
                               const TextSpan(text: " "),
                               TextSpan(
@@ -113,7 +118,6 @@ class _VideoStreamingSettingsPageState
                               ),
                             ],
                           ),
-                          textAlign: TextAlign.justify,
                           style: getEnteTextTheme(context).mini.copyWith(
                                 color: getEnteColorScheme(context).textMuted,
                               ),
@@ -145,10 +149,17 @@ class _VideoStreamingSettingsPageState
                       padding: const EdgeInsets.symmetric(horizontal: 12),
                       child: Text.rich(
                         TextSpan(
-                          text: AppLocalizations.of(context)
-                                  .videoStreamingDescription +
-                              "\n",
                           children: [
+                            TextSpan(
+                              text: AppLocalizations.of(context)
+                                  .videoStreamingDescriptionLine1,
+                            ),
+                            const TextSpan(text: "\n"),
+                            TextSpan(
+                              text: AppLocalizations.of(context)
+                                  .videoStreamingDescriptionLine2,
+                            ),
+                            const TextSpan(text: "\n"),
                             TextSpan(
                               text: AppLocalizations.of(context).moreDetails,
                               style: TextStyle(