bugfix: Replace 422 IDENTIFIER_MISMATCH with eSIM API specific code

[rkandoi]

What type of PR is this?

• bug

Which issue(s) this PR fixes:

Fixes #53

• Remove IDENTIFIER_MISTMATCH
• Corrected ESimProfileForDownload to only accept EID
• Clarifications in docs on the use of the dual EID and ICCID identifiers

[rkandoi]

@eric-murray - Please suggest if this is the fix for #53.

[eric-murray]

@eric-murray - Please suggest if this is the fix for #53.

Hi @rkandoi

Yes, fixing the error code was the only requirement for compliance with the Commonalities Design Guide. I can see that you are also working to improve the documentation, which is nobody's favourite task, but really does help potential users understand how to use the API.

Once the PRs are merged, create a new snapshot and I will be able to approve.