Copy cancel state to fake EntityExplodeEvent.

It's not clear if this change actually solves the underlying issue,
because it has not been tested in a controlled environment. However,
considering the EntityExplodeEvent constructor, which doesn't take a
cancel state value, and the `HIGHEST` priority setting of MobArena's
event handler, the issue is realistic, and this change very likely
solves the issue.

Fixes #704

changelog.md

@@ -32,6 +32,7 @@ These changes will (most likely) be included in the next version.
 - Reward groups with `nothing` in them no longer cause errors when earned/granted.
 - The title-based announcer and the title-based boss health bar have been fixed to work with the breaking change to the Title API in Spigot 1.17.
 - Arena Signs now correctly update for arenas that don't have `kebab-case` names in the config-file. 
+- Block explosion events cancelled by other plugins now remain cancelled unless MobArena specifically uncancels them for an arena.
 
 ## [0.106] - 2021-05-09
 ### Added

src/main/java/com/garbagemule/MobArena/listeners/MAGlobalListener.java

@@ -203,6 +203,7 @@ public class MAGlobalListener implements Listener
 
         // Account for Spigot's messy extra event
         EntityExplodeEvent fake = new EntityExplodeEvent(null, event.getBlock().getLocation(), blocks, event.getYield());
+        fake.setCancelled(event.isCancelled());
         entityExplode(fake);
 
         // Copy the values over