Document creating iOS export template ZIP

### Godot version

4.1 and master branch

### System information

MacOS 14.1 on MacBook Pro M1 Max

### Issue description

I followed the "Compiling for iOS" documentation [here](https://docs.godotengine.org/en/stable/contributing/development/compiling/compiling_for_ios.html) and compiling on MacOS Sonoma 14.1 went smoothly. However, the iOS Xcode template cannot be opened with Xcode 15.0.1 (the most current stable version). Xcode refuses to open it with the bland message:


I couldn't find any obvious issue with the syntax of the inner "pbxproj" file, so something else is broken.

I tried the 4.1 tagged source code, and the most recent master branch commit.

Any suggestions?

Cheers,
Martin

### Steps to reproduce

Clone the Godot source code (4.1 or main), navigate to "_misc/dist/ios_xcode_" and try opening the **godot_ios.xcodeproj** file with Xcode 15.0.1

### Minimal reproduction project

There is nothing to provide, as it is all in the official repo.