Simplify CertificateProvider setup

Summary:
Currently, certificateSetup is called in two places:
- processCertificateSigningRequest
- loadSecureServerConfig

`loadSecureServerConfig` is a mandatory step of Flipper server initialization ([ServerController.init](https://www.internalfb.com/code/flipper/[24785758018a2ffbd4751ad2b9093b5ef97c611d]/src/fbsource/xplat/sonar/desktop/flipper-server-core/src/comms/ServerController.tsx?lines=118)). Flipper cannot start without executing it.

As a result, calling `certificateSetup` in `processCertificateSigningRequest` always results in the early return.

This diff removes executing `certificateSetup` from `processCertificateSigningRequest`. Since it's called only during server setup (so only once), it no longer makes sense to use `didCertificateSetup`.

Next steps:
- Extract Android and iOS certificate utils. Remove the dependency on accessing adb/idb dynamically. See D33711652 (da618fd3f3).

Reviewed By: jknoxville

Differential Revision: D33817119

fbshipit-source-id: 675d1e2fe468782da458832c2e88259c92951fdb

desktop/flipper-server-core/src/utils/CertificateProvider.tsx

@@ -82,7 +82,6 @@ export type SecureServerConfig = {
  * Flipper CA.
  */
 export default class CertificateProvider {
-  private didCertificateSetup = false;
   private server: ServerController;
 
   constructor(server: ServerController) {
@@ -127,9 +126,6 @@ export default class CertificateProvider {
   };
 
   async certificateSetup() {
-    if (this.didCertificateSetup) {
-      return;
-    }
     if (isTest()) {
       throw new Error('Server certificates not available in test');
     } else {
@@ -138,7 +134,6 @@ export default class CertificateProvider {
         'ensureServerCertExists',
       );
     }
-    this.didCertificateSetup = true;
   }
 
   async processCertificateSigningRequest(
@@ -155,7 +150,6 @@ export default class CertificateProvider {
     const rootFolder = await promisify(tmp.dir)();
     const certFolder = rootFolder + '/FlipperCerts/';
     const certsZipPath = rootFolder + '/certs.zip';
-    await this.certificateSetup();
     const caCert = await this.getCACertificate();
     await this.deployOrStageFileForMobileApp(
       appDirectory,