Error on unsafeRandom() call in v1.3.4+

[sisyphusSmiling]

Problem

Calls to unsafeRandom() result in error. Bug persists in 1.3.4 & 1.4.0.

Steps to Reproduce

Execute the following script with the CLI versions 1.3.4 or 1.4.0

pub fun main(): UInt64 {
    return unsafeRandom()
}

Which will result in the following error:

❌ Command Error: client: rpc error: code = Unknown desc = [Error Code: 1057] error caused by: 1 error occurred:
	* [Error Code: 1101] cadence runtime error: Execution failed:
error: internal error: [Error Code: 1057] operation (Random) is not supported in this environment

Acceptance Criteria

The unsafeRandom API is still active (though undergoing refactor) so the call should function as it does with version 1.3.3 and older.

Context

Not currently blocked - using v1.3.3 instead - but came up when running Cadence tests locally.

[chasefleming]

@turbolent should this be supported after this PR? #1158

[turbolent]

Needs onflow/flow-emulator#459, which hasn't made it into a release yet

[turbolent]

cc @tarakby

[tarakby]

Although I triggered the issue on flow-go and then made a fix on flow-emulator, I have no visibility on emulator releases. Perhaps we could tag the emulator or Devex tools owner?

[btspoony]

Can we have a new release of Emulator for onflow/flow-emulator#459 to fix this?