Improve FCLoopIntegralToGraph for factorizing integrals

[vsht]

Here is an example of a factorizing 3-loop integral that cannot be properly graphed

FCLoopIntegralToGraph[
 SFAD[{{I*p1, 0}, {-m1^2, -1}, 1}]*
  SFAD[{{I*(p2 - p3), 0}, {-m1^5, -1}, 1}]*
  SFAD[{{I*(p3 + 0 q1), 0}, {-m1^2, -1}, 1}], {p1, p2, p3}, 
 VertexDegree -> 8]

Essentially, we need a routine that can detect obviously factorizing integrals and then run FCLoopIntegralToGraph on
each integral separately.

[vsht]

Here's another weird bug that needs attention

FCLoopIntegralToGraph[{FCTopology[
   "tri10", {SFAD[{{l1 + q1, 0}, {SMP["m_t"]^2, 1}, 1}], 
    SFAD[{{l1 + q1 + q2, 0}, {SMP["m_t"]^2, 1}, 1}], 
    SFAD[{{l1, 0}, {SMP["m_t"]^2, 1}, 1}], 
       SFAD[{{l2 - q1 - q2, 0}, {SMP["m_t"]^2, 1}, 1}], 
    SFAD[{{l2 - q2, 0}, {SMP["m_t"]^2, 1}, 1}], 
    SFAD[{{l1 - l2 + q1 + q2, 0}, {0, 1}, 1}], 
    SFAD[{{l2, 0}, {0, 1}, 1}]}, {l1, l2}, 
     {q1, q2}, {SPD[q1, q1] -> 0, SPD[q2, q2] -> 0, 
    SPD[q1, q2] -> s/2}, {}]}, Momentum -> {q1, q1 + q2, q1 - q2}]