First run hangs if IDE can't access Internet

Describe the problem

On the first run after a fresh installation, Arduino IDE downloads some files from the Internet:

The builtin:serial-discovery pluggable discovery tool
The builtin:mdns-discovery pluggable discovery tool
The Library Manager index
The primary Boards Manager package index

🐛 If the download of these files is not possible due to lack of Internet access, the startup hangs.

This is a change from Arduino IDE 1.x, which is in a fully functional state from the start with no hard dependency on an Internet connection (though obviously Library/Boards Manager can't be used).

To reproduce

Select File > Quit from the Arduino IDE menus if it is running.
Rename or delete (:warning: cautiously) the following folder to effectively simulate the environment of a first run:
- If you are using Windows:
```
C:\Users\<username>\AppData\Local\Arduino15
```
  (where <username> is your Windows username)
- If you are using Linux:
```
~/.arduino15
```
- If you are using macOS:
```
~/Library/Arduino15
```
Disconnect your computer from the Internet.
Start Arduino IDE.

🐛 Startup hangs at the startup animation.

🐛 The cause of the hang is not communicated to the user.

Expected behavior

Complete startup even when the essential resources could not be installed.

This is important because, once it has started up, Arduino IDE shows notifications that communicate the Internet access dependency to the user.

Record whether the arduino:avr and "Arduino_BuiltIn" installations were successful, and if not then retry on subsequent startups.
- Note: This must be done based on a dedicated record, and not on the presence/absence of these installations because users may have later removed unwanted installations after they were successfully installed automatically.

Arduino IDE version

097c92d904ca9b126e54b6a58030b5f4c650f075

Operating system

Windows

Operating system version

Additional context

The regression was introduced at https://github.com/arduino/arduino-ide/commit/a36524e02ab5fbc2ef333ff67a047dfe5718b306

The logs include this:

2023-05-03T23:57:19.823Z root ERROR Uncaught Exception: 
2023-05-03T23:57:19.823Z root ERROR Error: The index of the cores and libraries must be updated before initializing the core gRPC client.
The following problems were detected during the gRPC client initialization:
[platform-index] - code: 9, message: Loading index file: loading json index file C:\Users\per\AppData\Local\Arduino15\package_index.json: open C:\Users\per\AppData\Local\Arduino15\package_index.json: The system cannot find the file specified.
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:serial-discovery not found
[platform-index] - code: 9, message: Error loading hardware platform: discovery builtin:mdns-discovery not found
[library-index] - code: 9, message: Loading index file: reading library_index.json: open C:\Users\per\AppData\Local\Arduino15\library_index.json: The system cannot find the file specified.

    at isIndexUpdateRequiredBeforeInit (C:\arduino-tools\193-097c92d\resources\app\node_modules\arduino-ide-extension\lib\node\core-client-provider.js:388:11)
    at CoreClientProvider.evaluateErrorStatus (C:\arduino-tools\193-097c92d\resources\app\node_modules\arduino-ide-extension\lib\node\core-client-provider.js:200:16)
    at processTicksAndRejections (node:internal/process/task_queues:96:5)
    at async ClientReadableStreamImpl.<anonymous> (C:\arduino-tools\193-097c92d\resources\app\node_modules\arduino-ide-extension\lib\node\core-client-provider.js:184:31)

Additional reports:

Issue checklist

[X] I searched for previous reports in the issue tracker
[X] I verified the problem still occurs when using the latest nightly build
[X] My report contains all necessary details

arduino / arduino-ide