[#452] UI/update event extend mode (#454)

* Update event modal extend mode UI consistency

- Fix label font-size and fontWeight in extended mode to match normal mode
- Replace Lock icon with LockOutline icon for visibility toggle buttons
- Add displayEmpty prop to notification select to show default value

* Replace video icon with outlined variant for consistency

- Update VideocamIcon to VideocamOutlinedIcon in event form fields
- Update VideocamIcon to VideocamOutlinedIcon in event preview modal

src/components/Calendar/SettingsTab.tsx

@@ -1,5 +1,5 @@
 import FormatListBulletedIcon from "@mui/icons-material/FormatListBulleted";
-import LockIcon from "@mui/icons-material/Lock";
+import LockOutlineIcon from "@mui/icons-material/LockOutline";
 import PublicIcon from "@mui/icons-material/Public";
 import {
   Box,
@@ -99,7 +99,7 @@ export function SettingsTab({
             </ToggleButton>
 
             <ToggleButton value="private" sx={{ width: "140px" }}>
-              <LockIcon fontSize="small" sx={{ mr: 1 }} />
+              <LockOutlineIcon fontSize="small" sx={{ mr: 1 }} />
               {t("common.you")}
             </ToggleButton>
           </ToggleButtonGroup>