Fix #859 Improve the way to handle authorize fn errors in built-in receivers

[seratch]

Summary

This pull request closes #859 by improving the error handling of authorize function failures. As described here, the current implementation returns 500 Internal Server Error in the case and displays the following warn/error logs.

[WARN]  bolt-app Authorization of incoming event did not succeed. No listeners will be called.
[ERROR]  bolt-app Error: Failed fetching data from the Installation Store
    at new AuthorizationError (/path-to-app/node_modules/@slack/oauth/dist/errors.js:71:28)
    at InstallProvider.<anonymous> (/path-to-app/node_modules/@slack/oauth/dist/index.js:158:31)
    at step (/path-to-app/node_modules/@slack/oauth/dist/index.js:44:23)
    at Object.next (/path-to-app/node_modules/@slack/oauth/dist/index.js:25:53)
    at fulfilled (/path-to-app/node_modules/@slack/oauth/dist/index.js:16:58)
    at processTicksAndRejections (internal/process/task_queues.js:97:5) {
  code: 'slack_bolt_authorization_error'
}
[ERROR]   An unhandled error occurred while Bolt processed an event
[DEBUG]   Error details: Error: Failed fetching data from the Installation Store, storedResponse: undefined
[ERROR]   An incoming event was not acknowledged within 3 seconds. Ensure that the ack() argument is called in a listener.

As we recommend throwing an exception if there is no valid installation data in fetchInstallation method, this pattern should be handled as a normal case, not an internal server error.

This pull request fixes #364 too.

Requirements (place an x in each [ ])

• I've read and understood the Contributing Guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.

[codecov]

Codecov Report

Merging #891 (8c73ca6) into main (926b669) will decrease coverage by 5.52%.
The diff coverage is 23.52%.

❗ Current head 8c73ca6 differs from pull request most recent head d641204. Consider uploading reports for the commit d641204 to get more accurate results

@@            Coverage Diff             @@
##             main     #891      +/-   ##
==========================================
- Coverage   71.01%   65.48%   -5.53%     
==========================================
  Files          13       13              
  Lines        1235     1217      -18     
  Branches      362      359       -3     
==========================================
- Hits          877      797      -80     
- Misses        288      351      +63     
+ Partials       70       69       -1     

Impacted Files	Coverage Δ
src/receivers/HTTPReceiver.ts	16.47% <0.00%> (-15.55%)	⬇️
src/receivers/ExpressReceiver.ts	64.70% <14.28%> (-0.96%)	⬇️
src/App.ts	82.91% <100.00%> (-0.52%)	⬇️
src/receivers/SocketModeReceiver.ts	11.53% <0.00%> (-56.89%)	⬇️
src/receivers/render-html-for-install-path.ts	50.00% <0.00%> (-50.00%)	⬇️
src/errors.ts	91.48% <0.00%> (-8.52%)	⬇️
src/conversation-store.ts	92.30% <0.00%> (-7.70%)	⬇️
src/receivers/AwsLambdaReceiver.ts	59.49% <0.00%> (-0.51%)	⬇️
... and 4 more

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[seratch]

As we are aiming to release v3.4.0 within a few days and this pull request needs more time, let me move this one to v3.5 milestone.

[seratch]

I wanted to write some unit tests for this change but I found that it's not that simple and it may take longer than I thought. For this reason, I did some manual tests with example apps using npm link to the latest revision of the branch.

Example apps that I used for testing:

import { App } from '@slack/bolt';
const app = new App({
  signingSecret: process.env.SLACK_SIGNING_SECRET,
  authorize: async (_) => { throw new Error("Failed!"); }
});
(async () => {
  await app.start(Number(process.env.PORT) || 3000);
  console.log('⚡️ Bolt app is running!');
})();

import { App, ExpressReceiver } from '@slack/bolt';
const app = new App({
  receiver: new ExpressReceiver({ signingSecret: process.env.SLACK_SIGNING_SECRET!! }),
  authorize: async (_) => { throw new Error("Failed!"); }
});

[seratch]

This one is waiting for reviews

[mwbrooks]

LGTM!

[seratch]

resolved conflicts