fix(shared-data): add t20 lld settings to p50 version 3.5

Co-authored-by: Alex Joel <alex.copperman@opentrons.com>

Author: mjhuff

shared-data/pipette/definitions/2/geometry/single_channel/p50/3_5.json

@@ -12,6 +12,10 @@
     "A1": [-8.0, -22.0, -259.15]
   },
   "lldSettings": {
+    "t20": {
+      "minHeight": 1.5,
+      "minVolume": 0
+    },
     "t50": {
       "minHeight": 1.0,
       "minVolume": 0