FIX: Update errors correctly on array item remove

[sandhya-spend]

Follow up upon #75

When an array item is removed, the error associated with that array item needs to be removed, and the rest of the errors in the array need to be moved up.

[decrapifier]

	Warnings
⚠️	You should add at least 1 more reviewer to the PR

Coverage Report

👍 Test coverage is looking good.

Files	% Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
src/futil.js	100	100	100	100		✅
src/index.js	100	96.88	96.77	100		✅
src/mobx.js	94.87	88.24	100	94.87	10, 11	✅

and 2 more...

Files	% Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
src/util.js	100	100	100	100		✅
src/validators.js	52.38	100	50	52.38	6, 7, 8, 9, 10, 11, 12, 13, 14, 15	✅

Generated by 🚫 dangerJS against 445c877

[decrapifier]

Coverage Report

👍 Test coverage is looking good.

Files	% Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
src/futil.js	100	100	100	100		✅
src/index.js	100	96.88	96.77	100		✅
src/mobx.js	94.87	88.24	100	94.87	10, 11	✅

and 2 more...

Files	% Stmts	% Branch	% Funcs	% Lines	Uncovered Lines
src/util.js	100	100	100	100		✅
src/validators.js	52.38	100	50	52.38	6, 7, 8, 9, 10, 11, 12, 13, 14, 15	✅

Generated by 🚫 dangerJS against fbdc376

[stellarhoof]

Great job 👏