The types for the package `@metamask/eth-sig-util` were being
overwritten by a local type declaration. That has been removed, and all
type errors have been resolved.

All of the type errors were related to `normalize` returning
`undefined` if given a nullish input. We never pass it a nullish input,
but TypeScript wasn't able to infer that, so that issue was addressed
with type casts. This isn't ideal, but it's temporary. Once we finish
migrating all Keyrings to the new Keyring interface, we won't need to
normalize addresses anymore at all.

* Narrow return type of `signTypedMessage`

The method `signTypedMessage` always returns a string, but the declared
return type was `Bytes` (which is a type union of `string` along with
other things). This made the method more difficult to use, as callers
had to handle the other `Bytes` types as return values as well.

The method has been updated to use `string` as the return type.

* Narrow return type for encryption methods as well

The `signTypedMessage` parameter types accepted the data to sign as an
array. This works with `signTypedData_v1`, but is incompatible with
later versions.

The signature has been updated to accept data as either an array or an
object. Additionally, tests have been added to cover all three
supported versions of `signTypedData`.

* fix: add types for persistent and memory store

* fix: lint

* refactor: remove return from void function

* refactor: edit keyringBuilders type

* fix: make keyringBuilders arg optional

* rollback setLocked change

* Update src/KeyringController.test.ts

Co-authored-by: Elliot Winkler <elliot.winkler@gmail.com>

* refactor: rollback unlockKeyrings

---------

Co-authored-by: Elliot Winkler <elliot.winkler@gmail.com>

* Refactor controller initialization in tests

Each test now uses a helper function to construct the keyring
controller rather than using `beforeEach`. This eliminates redundant
redundancy in cases where the controller was being overwritten, and
makes it easier for future tests to customize how the controller is
initialized.

* Remove unnecessary submit password step

* Simplify types

The `KeyringController` method `addNewKeyring` was changed in v11 to
initialize the keyring options to an empty object. These options are
passed to the `deserialize` method of the keyring. This broke
compatibility with the QR keyring because its `deserialize` method does
not expect to be passed an empty object.

The `KeyringController` has been updated to no longer initialize the
`addNewKeyring` options to an empty object. It should now work the same
as it did prior to v11. The one functional difference is that it now
throws an error when `addNewKeyring` is used to add a simple keyring
without supplying any private keys, however that path would have
already thrown an error.

The `addNewKeyring` method has been updated to support non-object
keyring serialized state, which had been supported already on versions
prior to v11.

This allows us to remove a special-case for the simple keyring, which
requires a JSON array as its serialized keyring state.

When constructing a simple keyring, the method `addNewKeying` now
expects the second parameter (`opts`) to be an array of private keys
rather than an object with a `privateKeys` property. This is how it
worked prior to v11.