fix: Update chat interface styling and functionality

Based on the provided file summaries, here are the important bullet points for the commit message:

- Implemented improvements to the layout and styling of the chat interface, including positioning and styling for pinned files and alerts.
- Modified the scroll-down button and input group for a better user experience.
- Made adjustments to the modal for drawing canvas and PDF chat, including width, padding, and overflow properties.
- Updated the dataset section in the PDF chat modal for better readability and functionality.
- Updated mappings for `chat.css.map`.
- Made various changes to `chat.css`, including adding `z-index`, `position`, `width`, `padding`, `opacity`, and `height` attributes.

internal/tasks/gptchat/templates/scss/chat.scss

@@ -280,6 +280,8 @@
                             .operator {
                                 text-align: center;
                                 cursor: default;
+                                position: relative;
+                                z-index: 1;
 
                                 .btn {
                                     opacity: 0.6;