144 - no error handling for failure to create new donor

[esauerbo]

Describe the bug
Currently if the request to api/location/addDonors fails, the frontend will still indicate success. This is because the call to dispatchCreateNew in DonorsForm does not check the return code after creating a new donor.

To Reproduce
Introduce some sort of network error while making the request, or modify the frontend so an incorrect object is returned.

Expected behavior
A clear and concise description of what you expected to happen.

Screenshots
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Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.