refactor: remove Modal component and update styles

- Deleted the Modal component and its associated styles to streamline the codebase.
- Updated AuthDialog.scss to include necessary styles for the authentication modal.
- Enhanced index.scss with new styles for fullscreen dialogs and modal backgrounds.

Author: atyrode

src/frontend/src/styles/AuthDialog.scss

@@ -1,7 +1,7 @@
 /* Auth Modal Styles */
-@import './Modal.scss';
 
 .auth-modal {
+
   &__title-container {
     display: flex;
     align-items: center;

src/frontend/src/styles/Modal.scss

@@ -54,3 +54,23 @@ body {
     margin-left: 11px !important;
     font-size: 15px !important;
 }
+
+.excalidraw .Dialog--fullscreen {
+    .Dialog__close {
+        display: none;
+    }
+}
+
+.excalidraw .Modal__background {
+    background-color: rgba(0, 0, 0, 0.2);
+    backdrop-filter: blur(1px);
+    animation: Modal__background__fade-in 0.3s ease-out forwards !important;
+    
+    &.animations-disabled {
+        animation: none !important;
+    }
+}
+
+.excalidraw .Modal__content {
+    animation: Modal__content_fade-in 0.3s ease-out forwards !important;
+}