cli: enable BEEFY by default on test networks (#7293)

We consider BEEFY mature enough to run by default on all nodes
for test networks (Rococo/Wococo/Versi).

Right now, most nodes are not running it since it's opt-in using
--beefy flag. Switch to an opt-out model for test networks.

Replace --beefy flag from CLI with --no-beefy and have BEEFY
client start by default on test networks.

Signed-off-by: acatangiu <adrian@parity.io>

polkadot/cli/src/cli.rs

@@ -114,9 +114,10 @@ pub struct RunCmd {
 	#[arg(long = "grandpa-pause", num_args = 2)]
 	pub grandpa_pause: Vec<u32>,
 
-	/// Enable the BEEFY gadget (only on Rococo or Wococo for now).
+	/// Disable the BEEFY gadget
+	/// (currently enabled by default on Rococo, Wococo and Versi).
 	#[arg(long)]
-	pub beefy: bool,
+	pub no_beefy: bool,
 
 	/// Add the destination address to the jaeger agent.
 	///