Remove sendCommand from server.ts

[eleanorjboyd]

Currently there is a function called sendCommand in server.ts. This function was meant to be used in both pytest and unittest but it does not fit the requirements for pytest (additional parameters are needed). Therefore this code should be refactored to remove the sendCommand function and move logic into the test adapters per test.

[eleanorjboyd]

looking at this and the server.ts has an object PythonTestServer which extends ITestServer. I am ok to change the type definition of ITestServer to align with my needs for the new testing infrastructure right? @karthiknadig

export interface ITestServer {
    readonly onDataReceived: Event<DataReceivedEvent>;
    sendCommand(options: TestCommandOptions): Promise<void>;
    serverReady(): Promise<void>;
    getPort(): number;
    createUUID(cwd: string): string;
}

[karthiknadig]

We should change ITestServer to not include sendCommand.