Updated Upstream (Paper)

Upstream has released updates that appear to apply and compile correctly

Paper Changes:
PaperMC/Paper@aa8d38d Add forRemoval to material data deprecations (#10996)

gradle.properties

@@ -2,7 +2,7 @@ group = org.purpurmc.purpur
 version = 1.21-R0.1-SNAPSHOT
 
 mcVersion = 1.21
-paperCommit = 1f5db504244fe6563ab32cee646dad0c53360e01
+paperCommit = aa8d38d3dbab3cb0021d0f24f726818caf77bf15
 
 org.gradle.caching = true
 org.gradle.parallel = true