Fix #7743: Let stacked ASF LAMs transform (#7765)

Fixes #7743 

LAM extends (Biped) Mek, for these checks we shouldn't consider it a
Mek, it's treated as a vehicle.

Author: HammerGS

megamek/src/megamek/common/compute/Compute.java

@@ -562,7 +562,9 @@ public static Entity stackingViolation(Game game, Entity entering,
             return null;
         }
 
-        boolean isMek = (entering instanceof Mek)
+        // LAM in fighter mode shouldn't be treated as a Mek for all this
+        boolean isMek =
+              ((entering instanceof Mek) && !(entering instanceof LandAirMek lam && lam.getConversionMode() == LandAirMek.CONV_MODE_FIGHTER))
               || (entering instanceof SmallCraft);
         boolean isLargeSupport = (entering instanceof LargeSupportTank)
               || (entering instanceof Dropship)
@@ -667,9 +669,10 @@ public static Entity stackingViolation(Game game, Entity entering,
 
                     // If the entering entity is a mek, then any other mek in the hex is a violation. Unless grappled
                     // (but chain whip grapples don't count) grounded small craft are treated as meks for purposes
-                    // of stacking
+                    // of stacking. A LAM in fighter mode is not treated like a mek for this.
                     if (isMek
-                          && (((inHex instanceof Mek) && (inHex
+                          && ((((inHex instanceof Mek && !(entering instanceof LandAirMek lam
+                          && lam.getConversionMode() == LandAirMek.CONV_MODE_FIGHTER))) && (inHex
                           .getGrappled() != entering.getId() || inHex
                           .isChainWhipGrappled()))
                           || (inHex instanceof SmallCraft))) {