refactor: update markdown dependencies and enhance rendering capabilities

- Added flutter_markdown_plus as a new dependency for improved markdown rendering.
- Removed deprecated markdown_widget and related LaTeX handling, streamlining the codebase.
- Updated the ConduitMarkdown class to utilize the new markdown processing logic, enhancing maintainability.
- Improved the StreamingMarkdownWidget to leverage the updated markdown rendering methods, ensuring a cohesive user experience.
- Enhanced support for LaTeX and Mermaid diagrams within markdown content, providing better visual representation.

pubspec.lock

@@ -451,6 +451,14 @@ packages:
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_markdown_plus:
+    dependency: "direct main"
+    description:
+      name: flutter_markdown_plus
+      sha256: "7f349c075157816da399216a4127096108fd08e1ac931e34e72899281db4113c"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.5"
   flutter_math_fork:
     dependency: "direct main"
     description:
@@ -845,14 +853,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "7.3.0"
-  markdown_widget:
-    dependency: "direct main"
-    description:
-      name: markdown_widget
-      sha256: b52c13d3ee4d0e60c812e15b0593f142a3b8a2003cde1babb271d001a1dbdc1c
-      url: "https://pub.dev"
-    source: hosted
-    version: "2.3.2+8"
   matcher:
     dependency: transitive
     description:
@@ -1181,14 +1181,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.28.0"
-  scroll_to_index:
-    dependency: transitive
-    description:
-      name: scroll_to_index
-      sha256: b707546e7500d9f070d63e5acf74fd437ec7eeeb68d3412ef7b0afada0b4f176
-      url: "https://pub.dev"
-    source: hosted
-    version: "3.0.1"
   share_handler:
     dependency: "direct main"
     description:
@@ -1674,14 +1666,6 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.2.0"
-  visibility_detector:
-    dependency: transitive
-    description:
-      name: visibility_detector
-      sha256: dd5cc11e13494f432d15939c3aa8ae76844c42b723398643ce9addb88a5ed420
-      url: "https://pub.dev"
-    source: hosted
-    version: "0.4.0+2"
   vm_service:
     dependency: transitive
     description: