Change about page to be mounted in the web UI (#19345)

app/javascript/styles/mastodon/forms.scss

@@ -139,18 +139,9 @@ code {
   }
 
   .rules-list {
-    list-style: decimal;
     font-size: 17px;
     line-height: 22px;
-    font-weight: 500;
-    background: transparent;
-    border: 0;
-    padding: 0.5em 1em !important;
     margin-bottom: 30px;
-
-    li {
-      border-color: lighten($ui-base-color, 8%);
-    }
   }
 
   .hint {
@@ -603,41 +594,6 @@ code {
       }
     }
   }
-
-  &__overlay-area {
-    position: relative;
-
-    &__blurred form {
-      filter: blur(2px);
-    }
-
-    &__overlay {
-      position: absolute;
-      top: 0;
-      left: 0;
-      width: 100%;
-      height: 100%;
-      display: flex;
-      justify-content: center;
-      align-items: center;
-      background: rgba($ui-base-color, 0.65);
-      border-radius: 4px;
-      margin-left: -4px;
-      margin-top: -4px;
-      padding: 4px;
-
-      &__content {
-        text-align: center;
-
-        &.rich-formatting {
-          &,
-          p {
-            color: $primary-text-color;
-          }
-        }
-      }
-    }
-  }
 }
 
 .block-icon {
@@ -908,24 +864,7 @@ code {
   }
 }
 
-.table-form {
-  p {
-    margin-bottom: 15px;
-
-    strong {
-      font-weight: 500;
-
-      @each $lang in $cjk-langs {
-        &:lang(#{$lang}) {
-          font-weight: 700;
-        }
-      }
-    }
-  }
-}
-
-.simple_form,
-.table-form {
+.simple_form {
   .warning {
     box-sizing: border-box;
     background: rgba($error-value-color, 0.5);