refactor: Replace hardcoded monospace font with AppTypography constant

- Updated multiple instances of the 'monospace' font family to use AppTypography.monospaceFontFamily for consistency across the application.
- This change enhances maintainability and ensures a unified typography approach throughout the app.

lib/features/auth/views/authentication_page.dart

@@ -288,7 +288,7 @@ class _AuthenticationPageState extends ConsumerState<AuthenticationPage> {
                   hostText,
                   style: context.conduitTheme.bodySmall?.copyWith(
                     color: context.conduitTheme.textSecondary,
-                    fontFamily: 'monospace',
+                    fontFamily: AppTypography.monospaceFontFamily,
                   ),
                 ),
               ],

lib/features/auth/views/connection_issue_page.dart

@@ -151,7 +151,7 @@ class _ConnectionIssuePageState extends ConsumerState<ConnectionIssuePage> {
           textAlign: TextAlign.center,
           style: context.conduitTheme.bodyMedium?.copyWith(
             color: context.conduitTheme.textPrimary,
-            fontFamily: 'monospace',
+            fontFamily: AppTypography.monospaceFontFamily,
           ),
         ),
         const SizedBox(height: Spacing.xs),

lib/features/auth/views/server_connection_page.dart

@@ -721,7 +721,7 @@ class _ServerConnectionPageState extends ConsumerState<ServerConnectionPage> {
                   entry.value,
                   style: context.conduitTheme.bodySmall?.copyWith(
                     color: context.conduitTheme.textSecondary,
-                    fontFamily: 'monospace',
+                    fontFamily: AppTypography.monospaceFontFamily,
                   ),
                   overflow: TextOverflow.ellipsis,
                 ),