fix: npm ci and typescript compilation errors

[lucinvitae]

Fixes issues found when running npm ci and typescript compilation errors for npm run build. e.g. output:

npm run build                                            

> supergateway@2.8.3 build
> tsc -p tsconfig.build.json

src/gateways/stdioToWs.ts:120:26 - error TS2345: Argument of type 'WebSocketServerTransport' is not assignable to parameter of type 'Transport'.
  Types of property 'send' are incompatible.
    Type '(msg: JSONRPCMessage, clientId?: string | undefined) => Promise<void>' is not assignable to type '(message: JSONRPCMessage, options?: TransportSendOptions | undefined) => Promise<void>'.
      Types of parameters 'clientId' and 'options' are incompatible.
        Type 'TransportSendOptions | undefined' is not assignable to type 'string | undefined'.
          Type 'TransportSendOptions' is not assignable to type 'string'.

120     await server.connect(wsTransport)
                             ~~~~~~~~~~~

src/server/websocket.ts:68:9 - error TS2416: Property 'send' in type 'WebSocketServerTransport' is not assignable to the same property in base type 'Transport'.
  Type '(msg: JSONRPCMessage, clientId?: string | undefined) => Promise<void>' is not assignable to type '(message: JSONRPCMessage, options?: TransportSendOptions | undefined) => Promise<void>'.
    Types of parameters 'clientId' and 'options' are incompatible.
      Type 'TransportSendOptions | undefined' is not assignable to type 'string | undefined'.
        Type 'TransportSendOptions' is not assignable to type 'string'.

68   async send(msg: JSONRPCMessage, clientId?: string): Promise<void> {
           ~~~~


Found 2 errors in 2 files.

Errors  Files
     1  src/gateways/stdioToWs.ts:120
     1  src/server/websocket.ts:68