Reinitialize should allow to override existing config in collationGeneration (#4833)

Currently the `Initialize` and `Reinitialize` messages in the
collationGeneration subsystem fail if:
-  `Initialize` if there exists already another configuration and
- `Reinitialize` if another configuration does not exist

I propose to instead change the behaviour of `Reinitialize` to always
set the config regardless of whether one exists or not.

---------

Co-authored-by: Bastian Köcher <git@kchr.de>
Co-authored-by: Andrei Sandu <54316454+sandreim@users.noreply.github.com>

polkadot/node/collation-generation/src/lib.rs

@@ -147,11 +147,7 @@ impl CollationGenerationSubsystem {
 			Ok(FromOrchestra::Communication {
 				msg: CollationGenerationMessage::Reinitialize(config),
 			}) => {
-				if self.config.is_none() {
-					gum::error!(target: LOG_TARGET, "no initial initialization");
-				} else {
-					self.config = Some(Arc::new(config));
-				}
+				self.config = Some(Arc::new(config));
 				false
 			},
 			Ok(FromOrchestra::Communication {

prdoc/pr_4833.prdoc

+title: "Reinitialize should allow to override existing config in collationGeneration"
+
+doc:
+  - audience: Node Dev
+    description: |
+      The Reinitialize collationGeneration subsystem message currently fails if no other config is already set.
+      As it is difficult to query the collationGeneration subsystem to check when to call Initialize or Reinitialize, this PR
+      proposes that Reinitialize overrides the configuration regardless if there was one already set.
+
+crates:
+  - name: polkadot-node-collation-generation
+    bump: minor