Fix recomposition failing for child components

[brpowell]

What does this PR do?

Fixes source conversion for child components of a decomposed type. The issue was during the manifest generation step where the type "did not exist" for the child component. The registry access getTypeFromName only supports getting top level types at the moment so this doesn't work as expected.

This issue came up after a failed rebase/merge in the last PR 🤦‍♂️

What issues does this PR fix or reference?

@W-7672773@

Functionality Before

 UnhandledPromiseRejectionWarning: TypeInferenceError: Missing metadata type definition in registry for id 'customfield'
    at RegistryAccess.getTypeFromName (/Users/b.powell/dev/source-deploy-retrieve/lib/src/metadata-registry/registryAccess.js:46:19)
    at ManifestGenerator.createMetadataMap (/Users/b.powell/dev/source-deploy-retrieve/lib/src/metadata-registry/manifestGenerator.js:45:54)
    at ManifestGenerator.createManifest (/Users/b.powell/dev/source-deploy-retrieve/lib/src/metadata-registry/manifestGenerator.js:30:34)
    at MetadataConverter.<anonymous> (/Users/b.powell/dev/source-deploy-retrieve/lib/src/convert/metadataConverter.js:35:60)
    at Generator.next (<anonymous>)
    at /Users/b.powell/dev/source-deploy-retrieve/lib/src/convert/metadataConverter.js:8:71
    at new Promise (<anonymous>)
    at __awaiter (/Users/b.powell/dev/source-deploy-retrieve/lib/src/convert/metadataConverter.js:4:12)
    at MetadataConverter.convert (/Users/b.powell/dev/source-deploy-retrieve/lib/src/convert/metadataConverter.js:31:16)
    at test (repl:8:26)
(node:11032) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)
(node:11032) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

Functionality After

Working as expected

[brpowell]

Instead of asking the RegistryAccess for the type, this just pulls it right off the component since we have that information already. getTypeFromName currently only supports top level metadata types. If we feel like it's necessary to strictly enforce a metadata type defined in the registry.json file to use the manifest generator, this could be done instead:

const { name: typeName } = component.parent
        ? this.registryAccess.getTypeFromName(component.parent.type.name).children.types[
            component.type.id
          ]
        : this.registryAccess.getTypeFromName(component.type.name);

Most of the time however, components are constructed from the registry code and even the type property itself is strictly typed.

[jag-j]

Prettier fix - "," at the end