Fix symbol entry in the in-call dialpad (#6521)

The field had RTL direction set on it, which meant symbols, like *,
appeared at the beginning of the field instead of the end.

RTL was introduced in
https://github.com/matrix-org/matrix-react-sdk/pull/5786,
however its removal seems to have had no adverse affects
from testing.

res/css/views/voip/_DialPadContextMenu.scss

@@ -69,7 +69,6 @@ limitations under the License.
     overflow: hidden;
     max-width: 185px;
     text-align: left;
-    direction: rtl;
     padding: 8px 0px;
     background-color: rgb(0, 0, 0, 0);
 }