MDL-88054 tool_mfa: ensure factor preference icons are circular.

They were once, but then weren't. Probably same cause as that fixed
in 0ff8f7b2 for all emoticons.

admin/tool/mfa/styles.css

@@ -38,3 +38,8 @@ input.tool-mfa-verification-code,
 .mfa-verify-form .form-group.fitem > span > input {
     width: 100%;
 }
+
+#mfalist .icon-circle .icon {
+    width: 64px;
+    height: 64px;
+}

theme/boost/scss/moodle/icons.scss

@@ -266,6 +266,8 @@ img.icon {
     .icon {
         margin: 0;
         text-align: center;
+        width: unset;
+        height: unset;
         max-width: unset;
         max-height: unset;
         color: $black;

theme/boost/style/moodle.css

@@ -28939,6 +28939,8 @@ img.icon {
 .icon-circle .icon {
   margin: 0;
   text-align: center;
+  width: unset;
+  height: unset;
   max-width: unset;
   max-height: unset;
   color: #000;

theme/classic/style/moodle.css

@@ -28939,6 +28939,8 @@ img.icon {
 .icon-circle .icon {
   margin: 0;
   text-align: center;
+  width: unset;
+  height: unset;
   max-width: unset;
   max-height: unset;
   color: #000;