docs: Fix out-of-sequence instructions (#1684)

docs: Pre-PR version sends you to install CLI, which tells you to create a project. Then, when you come back, you get told to create a project again (with additional requirements).

This PR improves the UX by fixing this issue.

docs/firebase.md

@@ -6,7 +6,6 @@ as callable functions using the Cloud Functions client libraries.
 
 ## Before you begin
 
-*   Install the [Firebase CLI](/docs/cli).
 *   You should be familiar with Genkit's concept of [flows](flows), and how to
     write them. The instructions on this page assume that you already have some
     flows defined, which you want to deploy.
@@ -24,6 +23,8 @@ up, follow these steps:
 1.  Upgrade the project to the Blaze plan, which is required to deploy Cloud
     Functions.
 
+1.  Install the [Firebase CLI](/docs/cli).
+
 1.  Log in with the Firebase CLI:
 
     ```posix-terminal