Throw exception rather than allow php fail

[eileenmcnaughton]

Overview

Throw exception rather than allow php fail when the api class is not found

Before

After

Technical Details

This seems to be something I hit fairly often locally - due to inconsistent states or whatever - and it's always a pain to figure out the entity in question

Comments

[civibot]

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[monishdeb]

Patch looks good, confirmed that it fixes the notice, and rightful show exception message. Merging now