feat: enforce async request redirect URL is in the snaps 'allowedOrigins'

[k-g-j]

Description

Currently, in the async flow, we do not check that the redirect URL matches a domain of one of the allowed origins present in the Snap's manifest, and this has to be checked during the Snap review process. This change will add an additional check when receiving an async request that verifies whether or not the URL domain is within the Snap's allowed origins.

• Fixes #102
• See: #270

Testing

Coverage remains at 100%

Test Coverage Report

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	100	100	100	100
CaseInsensitiveMap.ts	100	100	100	100
DeferredPromise.ts	100	100	100	100
KeyringSnapControllerClient.ts	100	100	100	100
SnapIdMap.ts	100	100	100	100
SnapKeyring.ts	100	100	100	100
index.ts	100	100	100	100
types.ts	100	100	100	100
util.ts	100	100	100	100

Jest

yarn jest src/SnapKeyring.test.ts -t "throws an error if async request redirect url is not an allowed origin" yarn jest src/SnapKeyring.test.ts -t "throws an error if no allowed origins and async request redirect url"