[NEW] Make font of unread items bolder for better contrast (#8602)

* Make font of unread items bolder for better conrttrast - fixes #8599

* Update sidebar-item.css

packages/rocketchat-theme/client/imports/components/sidebar/sidebar-item.css

@@ -100,6 +100,7 @@
 	&--unread,
 	&--mention {
 		color: var(--sidebar-item-unread-color);
+		font-weight: var(--sidebar-item-unread-font-weight);
 	}
 
 	&__popup-active {

packages/rocketchat-theme/client/imports/general/variables.css

@@ -205,6 +205,7 @@
 	--sidebar-item-active-background: var(--rc-color-primary-dark);
 	--sidebar-item-active-color: var(--sidebar-item-text-color);
 	--sidebar-item-unread-color: var(--color-white);
+	--sidebar-item-unread-font-weight: 700;
 	--sidebar-item-popup-background: var(--color-dark-medium);
 	--sidebar-item-user-status-size: 6px;
 	--sidebar-item-user-status-radius: 50%;