fix: defer AdobeMedia one-time init until launchAppId is available

[denischilik]

Background

AdobeMedia startup could consume its one-time initialization path before launchAppId was available, preventing later initialization in the same process. This update ensures initialization is attempted only when configuration is present.

What Has Changed

• Added an early launchAppId guard before entering the one-time initialization block
• Prevented dispatch_once from executing in unconfigured startup states
• Kept AdobeMedia initialization flow unchanged once configuration is available

Screenshots/Video

N/A

Checklist

• I have performed a self-review of my own code.
• I have made corresponding changes to the documentation.
• I have added tests that prove my fix is effective or that my feature works.
• I have tested this locally.

Additional Notes

• This is a targeted initialization-order fix in MPKitAdobeMedia.start.