Doctor complains Android SDK is not installed

Summary:
There are complaints about Android SDK being reported as "not installed" when it is actually installed. To address them, I changed the way how we detect SDK and also added some minimal actionable feedback for each check.

The problem with the previous implementation of Android SDK check via "envinfo" is that the library uses "sdkmanager" tool under the hood, and this tool doesn't work on Java 9+. To fix this I'm changing the way how we assume SDK is installed to simple check for "adb" tool existence.

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Reviewed By: jknoxville

Differential Revision: D19517769

fbshipit-source-id: 1c21f1bdcd05c7c0ae3f97b9c3454efa2c861d26

src/utils/runHealthchecks.tsx

@@ -66,14 +66,14 @@ async function launchHealthchecks(options: HealthcheckOptions): Promise<void> {
         checkResult.hasProblem && h.isRequired
           ? {
               status: 'FAILED',
-              helpUrl: checkResult.helpUrl,
+              message: checkResult.message,
             }
           : checkResult.hasProblem && !h.isRequired
           ? {
               status: 'WARNING',
-              helpUrl: checkResult.helpUrl,
+              message: checkResult.message,
             }
-          : {status: 'SUCCESS'};
+          : {status: 'SUCCESS', message: checkResult.message};
       options.updateHealthcheckResult(categoryKey, h.key, result);
     }
   }