test: Replace 0xC0 constant

Instead it should be the named constant `LEAF_VERSION_TAPSCRIPT`.

Github-Pull: #27143
Rebased-From: c3b4b5a
(cherry picked from commit c3b4b5a)

Author: roconnor-blockstream

test/functional/feature_taproot.py

@@ -688,7 +688,7 @@ def spenders_taproot_active():
     # Reusing the scripts above, test that various features affect the sighash.
     add_spender(spenders, "sighash/annex", tap=tap, leaf="pk_codesep", key=secs[1], hashtype=hashtype, standard=False, **SINGLE_SIG, annex=bytes([ANNEX_TAG]), failure={"sighash": override(default_sighash, annex=None)}, **ERR_SIG_SCHNORR)
     add_spender(spenders, "sighash/script", tap=tap, leaf="pk_codesep", key=secs[1], **common, **SINGLE_SIG, failure={"sighash": override(default_sighash, script_taproot=tap.leaves["codesep_pk"].script)}, **ERR_SIG_SCHNORR)
-    add_spender(spenders, "sighash/leafver", tap=tap, leaf="pk_codesep", key=secs[1], **common, **SINGLE_SIG, failure={"sighash": override(default_sighash, leafversion=random.choice([x & 0xFE for x in range(0x100) if x & 0xFE != 0xC0]))}, **ERR_SIG_SCHNORR)
+    add_spender(spenders, "sighash/leafver", tap=tap, leaf="pk_codesep", key=secs[1], **common, **SINGLE_SIG, failure={"sighash": override(default_sighash, leafversion=random.choice([x & 0xFE for x in range(0x100) if x & 0xFE != LEAF_VERSION_TAPSCRIPT]))}, **ERR_SIG_SCHNORR)
     add_spender(spenders, "sighash/scriptpath", tap=tap, leaf="pk_codesep", key=secs[1], **common, **SINGLE_SIG, failure={"sighash": override(default_sighash, leaf=None)}, **ERR_SIG_SCHNORR)
     add_spender(spenders, "sighash/keypath", tap=tap, key=secs[0], **common, failure={"sighash": override(default_sighash, leaf="pk_codesep")}, **ERR_SIG_SCHNORR)