DEV: Fix or disable various lint rules (#24630)

A grab bag of smaller issues (constructor-super, no-fallthrough, ember/no-private-routing-service, no-unreachable, no-async-promise-executor)

app/assets/javascripts/discourse-widget-hbs/lib/widget-hbs-compiler.js

@@ -98,13 +98,10 @@ function mustacheValue(node, state) {
         opts ? argValue(opts) : opts
       }, ${otherOpts ? argValue(otherOpts) : otherOpts})`;
 
-      break;
     case "yield":
       return `this.attrs.contents()`;
-      break;
     case "i18n":
       return i18n(node);
-      break;
     case "avatar":
       let template = argValue(
         node.hash.pairs.find((p) => p.key === "template")
@@ -117,13 +114,10 @@ function mustacheValue(node, state) {
         state,
         "avatar"
       )}(${size}, { template: ${template}, username: ${username} })`;
-      break;
     case "date":
       return `${useHelper(state, "dateNode")}(${valueOf(node.params[0])})`;
-      break;
     case "d-icon":
       return `${useHelper(state, "iconNode")}(${valueOf(node.params[0])})`;
-      break;
     default:
       // Shortcut: If our mustache has hash arguments, we can assume it's attaching.
       // For example `{{home-logo count=123}}` can become `this.attach('home-logo, { "count": 123 });`
@@ -146,7 +140,6 @@ function mustacheValue(node, state) {
           path
         )} + '</span>'})`;
       }
-      break;
   }
 }
 
@@ -232,6 +225,7 @@ class Compiler {
         switch (node.path.original) {
           case "unless":
             negate = "!";
+          // eslint-disable-next-line no-fallthrough
           case "if":
             instructions.push(
               `if (${negate}${resolve(node.params[0].original)}) {`