fix: correct giga_executor TOML key from giga_enabled to enabled

The legacy writer was emitting [giga_executor] giga_enabled which does
not match the seid viper key giga_executor.enabled, causing the Giga
Executor to always read as disabled.

Author: bdchatham

legacy.go

@@ -318,7 +318,7 @@ type legacyWASM struct {
 }
 
 type legacyGigaExecutor struct {
-	Enabled    bool `toml:"giga_enabled"`
+	Enabled    bool `toml:"enabled"`
 	OccEnabled bool `toml:"occ_enabled"`
 }