chore: remove obsolete css vendor prefixes (#739)

Co-authored-by: Dominik Pschenitschni <mail@celement.de>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/739
Reviewed-by: konrad <k@knt.li>
Co-authored-by: dpschen <dpschen@noreply.kolaente.de>
Co-committed-by: dpschen <dpschen@noreply.kolaente.de>

src/styles/components/gantt.scss

@@ -74,12 +74,7 @@ $gantt-vertical-border-color: $grey-100;
 				position: relative;
 				height: 31px !important;
 
-				-webkit-touch-callout: none; // iOS Safari
-				-webkit-user-select: none; // Safari
-				-khtml-user-select: none; // Konqueror HTML
-				-moz-user-select: none; // Firefox
-				-ms-user-select: none; // Internet Explorer/Edge
-				user-select: none; // Non-prefixed version, currently  supported by Chrome and Opera
+				user-select: none;
 
 				&.is-current-edit {
 					border-color: $orange !important;

src/styles/components/kanban.scss

@@ -62,12 +62,7 @@ $filter-container-height: '1rem - #{$switch-view-height}';
 			}
 
 			.task {
-				-webkit-touch-callout: none; // iOS Safari
-				-webkit-user-select: none; // Safari
-				-khtml-user-select: none; // Konqueror HTML
-				-moz-user-select: none; // Old versions of Firefox
-				-ms-user-select: none; // Internet Explorer/Edge
-				user-select: none; // Non-prefixed version, currently supported by Chrome, Opera and Firefox
+				user-select: none;
 
 				//transition: $ease-out;
 				cursor: pointer;

src/styles/components/modal.scss

@@ -79,6 +79,5 @@
 
 .modal-enter .modal-container,
 .modal-leave-active .modal-container {
-  -webkit-transform: scale(0.9);
   transform: scale(0.9);
 }

src/styles/components/switch-view.scss

@@ -13,10 +13,6 @@
     display: block;
     border-radius: $radius;
 
-    -webkit-transition: all 100ms;
-    -moz-transition: all 100ms;
-    -ms-transition: all 100ms;
-    -o-transition: all 100ms;
     transition: all 100ms;
 
     &:not(:last-child) {