feat: Add a means to detect if the CLI binary exists

index.d.ts

@@ -130,6 +130,7 @@ declare namespace SentryCliPlugin {
 declare class SentryCliPlugin implements WebpackPluginInstance {
   options: SentryCliPlugin.SentryCliPluginOptions;
   constructor(options: SentryCliPlugin.SentryCliPluginOptions);
+  static cliBinaryExists(): string;
   apply(compiler: Compiler): void;
 }
 

src/index.js

@@ -1,4 +1,5 @@
 const SentryCli = require('@sentry/cli');
+const fs = require('fs');
 const path = require('path');
 const util = require('util');
 const { RawSource } = require('webpack-sources');
@@ -193,6 +194,10 @@ class SentryCliPlugin {
     return this.options.dryRun === true;
   }
 
+  static cliBinaryExists() {
+    return fs.existsSync(SentryCli.getPath());
+  }
+
   /** Creates a new Sentry CLI instance. */
   getSentryCli() {
     const cli = new SentryCli(this.options.configFile, {