SafeguardA2AContext: getRetrievableAccounts throws NullPointerException when API key is null

[msawberger]

Line 135: account.setApiKey(retrieval.getApiKey().toCharArray());
If the api key is not included in the response the toCharArray will cause a null pointer exception to occur.

[bnicholesdell]

This is actually an issue with SPP 7.1. SPP should always return an API key. This bug has been fixed in SPP 7.2. A workaround for this bug will also be included in the next release of SafeguardJava to allow the call to succeed even without the API key.

[bnicholesdell]

Add null check for api key. #118