Align displayName to the right side when mxId is rendered

Since displayName on ReplyChain is aligned to the left side on our UI as well, the default way of displaying and hiding mxId with visibility declaration is set to be applied.

This commit also fixes the variable for line height, removing `unset` as it is no longer necessary.

res/css/_sc/views/rooms/_IRCLayout.pcss

@@ -28,6 +28,31 @@ limitations under the License.
     }
 }
 
+@define-mixin sc_DisambiguatedProfile_visibility {
+    .mx_DisambiguatedProfile {
+        > .mx_DisambiguatedProfile_mxid {
+            display: none;
+        }
+
+        &:hover {
+            > .mx_DisambiguatedProfile_mxid {
+                display: unset;
+            }
+        }
+    }
+
+    .mx_ReplyChain_wrapper .mx_ReplyChain .mx_DisambiguatedProfile {
+        /* Stop mxid from moving avatar up on ReplyChain by resetting display
+           value "none" defined above, in order to make visibility declaration
+           effective */
+        /* Mind difference of avatar placement between on upstream's
+           mx_EventTile and mx_ReplyTile_sender */
+        > .mx_DisambiguatedProfile_mxid {
+            display: unset;
+        }
+    }
+}
+
 @define-mixin sc_DisambiguatedProfile {
     .mx_DisambiguatedProfile {
         /* Align elements to the end side */
@@ -50,6 +75,8 @@ limitations under the License.
             padding-inline-start: 0; /* Remove the value specified on upstream since var(--right-padding) is specified for mx_DisambiguatedProfile_displayName above */
         }
     }
+
+    @mixin sc_DisambiguatedProfile_visibility;
 }
 
 @define-mixin sc_BaseAvatar {
@@ -84,9 +111,7 @@ limitations under the License.
             }
 
             .mx_DisambiguatedProfile {
-                --cpd-font-body-md-regular: var(--line-height); /* Fix the line-height value specified with Compound for IRC layout */
-
-                display: unset; /* Unset the inherited value */
+                --cpd-font-line-height-regular: var(--line-height); /* Fix the line-height value specified with Compound for IRC layout */
             }
         }
     }