Search for events with a pair of displaced vertices from long-lived neutral particles decaying into hadronic jets in the ATLAS muon spectrometer in <math display='"inline"'> <mi>p</mi> <mi>p</mi> </math> collisions at <math display='"inline"'> <msqrt> <mi>s</mi> </msqrt> <mo>=</mo> <mn>13</mn></math>