add a default option to the cannot pair dialog (microsoft#10432)

* add a default option to the cannot pair dialog

* open the hw dialog if a webusb device has not been selected to connect

* keeping isarcade check separate from the reasonunsupported switch statement

* make the changes so the behavior is close to live

* update the default message

Co-authored-by: Thomas Sparks <[email protected]>

---------

Co-authored-by: Thomas Sparks <[email protected]>

Author: srietkerk

pxtlib/main.ts

@@ -339,6 +339,10 @@ namespace pxt {
             })
     }
 
+    export function getActiveHwVariant(): string {
+        return hwVariant
+    }
+
     export interface PxtOptions {
         debug?: boolean;
         light?: boolean; // low resource device

webapp/src/editortoolbar.tsx

@@ -211,6 +211,7 @@ export class EditorToolbar extends data.Component<ISettingsProps, EditorToolbarS
     protected onCannotPairClick = async () => {
         pxt.tickEvent("editortools.pairunsupported", undefined, { interactiveConsent: true });
         const reasonUnsupported = await pxt.usb.getReasonUnavailable();
+
         let modalBody: string;
         switch (reasonUnsupported) {
             case "security":
@@ -225,6 +226,9 @@ export class EditorToolbar extends data.Component<ISettingsProps, EditorToolbarS
             case "notimpl":
                 modalBody = lf("WebUSB is not supported by this browser; please check for updates.");
                 break;
+            default:
+                modalBody = lf("Unable to connect to WebUSB. Please try refreshing the page.");
+                break;
         }
 
         dialogAsync({
@@ -275,9 +279,11 @@ export class EditorToolbar extends data.Component<ISettingsProps, EditorToolbarS
 
         const boards = pxt.appTarget.simulator && !!pxt.appTarget.simulator.dynamicBoardDefinition;
         const editorSupportsWebUSB = pxt.appTarget?.compile?.webUSB;
+        const hardwareVariantSelected = (pxt.appTarget.alwaysMultiVariant || !pxt.appTarget.variants || !!(pxt.getActiveHwVariant()))
         const webUSBSupported = pxt.usb.isEnabled && editorSupportsWebUSB;
         const showUsbNotSupportedHint = editorSupportsWebUSB
             && !pxt.usb.isEnabled
+            && hardwareVariantSelected
             && pxt.shell.getControllerMode() !== pxt.shell.ControllerMode.App
             && !pxt.BrowserUtils.isPxtElectron()
             && (pxt.BrowserUtils.isChromiumEdge() || pxt.BrowserUtils.isChrome());