scripted-diff: rename gbt_force and gbt_force_name

The term "force" is ambiguous and not used in BIP9 where the ! rule
prefix is introduced.

Additionally, #29039 renamed gbt_vb_name to gbt_force_name which
might increase the confusion.

-BEGIN VERIFY SCRIPT-
sed -i s/gbt_force_name/gbt_rule_value/g ./src/rpc/mining.cpp
sed -i s/gbt_force/gbt_optional_rule/g $(git grep -l gbt_force)
-END VERIFY SCRIPT-

src/deploymentinfo.cpp

@@ -11,11 +11,11 @@
 const std::array<VBDeploymentInfo,Consensus::MAX_VERSION_BITS_DEPLOYMENTS> VersionBitsDeploymentInfo{
     VBDeploymentInfo{
         .name = "testdummy",
-        .gbt_force = true,
+        .gbt_optional_rule = true,
     },
     VBDeploymentInfo{
         .name = "taproot",
-        .gbt_force = true,
+        .gbt_optional_rule = true,
     },
 };