Adds link to AI Studio when entering Gemini key (#2780)

I used ai.dev as the alternate URL as it takes up less space but if this
is likely to confuse users we can use the long form.

Co-authored-by: Tony Kipkemboi <iamtonykipkemboi@gmail.com>

src/crewai/cli/constants.py

@@ -13,7 +13,7 @@ ENV_VARS = {
     ],
     "gemini": [
         {
-            "prompt": "Enter your GEMINI API key (press Enter to skip)",
+            "prompt": "Enter your GEMINI API key from https://ai.dev/apikey (press Enter to skip)",
             "key_name": "GEMINI_API_KEY",
         }
     ],