Subcircuit edge case for pin which is getting connected by other pins of outer subcircuit (Fails in fake-autorouter)

[imrishabh18]

Edge case with subcircuit, when a pin is getting connected by more than 2 pins. On conversion of circuit-json -> dsn -> circuit-json (which happens for testing fake-autorouter). We get a source_trace which is having an array of connected_source_port_ids which includes the port traces which are connected among themselves in another source_trace.

<board width="10mm" height="10mm" autorouter={cloudAutorouterConfig}>
      <subcircuit name="S1" autorouter={cloudAutorouterConfig}>
        <resistor
          resistance="1k"
          footprint="0402"
          name="R1"
          schX={3}
          pcbX={3}
        />
        <resistor
          resistance="1k"
          footprint="0402"
          name="R2"
          schX={3}
          pcbX={3}
          pcbY={2}
        />
        <trace from=".R1 .pin1" to=".R2 .pin2" />
      </subcircuit>
      <subcircuit name="S2">
        <capacitor
          capacitance="1000pF"
          footprint="0603"
          name="C1"
          schX={-3}
          pcbX={-3}
        />
        <trace from=".C1 .pin1" to=".C1 .pin2" />
      </subcircuit>
      <trace from=".S1 .R1 .pin1" to=".S2 .C1 .pin1" />
    </board>