Custom terminal fonts support (#5414)

Fixes #5132 #5133 
- bundled 7 new monospaced fonts for terminal
- fix: refresh terminal font after changing in the preferences / keep cluster iframe accessible in DOM while not active/focused
- display terminal's custom font preview with font-name in the select-box + live-preload for current `fontSize`, fix lint

* Fixes for <Input/>:
- remove duplicated error messages for sync validators
- don't propagate invalid values on change (uncontrolled components only)
- more informative error message for numeric input with min/max info

src/renderer/components/cluster-manager/cluster-frame-handler.ts

@@ -45,7 +45,6 @@ export class ClusterFrameHandler {
 
     iframe.id = `cluster-frame-${cluster.id}`;
     iframe.name = cluster.contextName;
-    iframe.style.display = "none";
     iframe.setAttribute("src", getClusterFrameUrl(clusterId));
     iframe.addEventListener("load", action(() => {
       logger.info(`[LENS-VIEW]: frame for clusterId=${clusterId} has loaded`);
@@ -95,7 +94,7 @@ export class ClusterFrameHandler {
     ipcRenderer.send(clusterVisibilityHandler);
 
     for (const { frame: view } of this.views.values()) {
-      view.style.display = "none";
+      view.classList.add("hidden");
     }
 
     const cluster = clusterId
@@ -113,9 +112,9 @@ export class ClusterFrameHandler {
 
           return undefined;
         },
-        (view) => {
+        (view: LensView) => {
           logger.info(`[LENS-VIEW]: cluster id=${clusterId} should now be visible`);
-          view.frame.style.display = "flex";
+          view.frame.classList.remove("hidden");
           ipcRenderer.send(clusterVisibilityHandler, clusterId);
         },
       );

src/renderer/components/cluster-manager/cluster-manager.scss

@@ -35,7 +35,20 @@
     background-color: var(--mainBackground);
 
     iframe {
+      position: absolute;
+      left: 0;
+      top: 0;
+      width: 100%;
+      height: 100%;
+      display: flex;
       flex: 1;
+
+      // when updating font settings in the "Preferences -> Terminal" cluster's iframe
+      // must be accessible in DOM (e.g. elem.getBoundingClientRect() must work)
+      &.hidden {
+        opacity: 0;
+        pointer-events: none;
+      }
     }
   }
 }