Update duo chat include context ff

What does this MR do and why?

Updates duo_include_context_file and duo_additional_context flag for duo chat to be enabled by default.

The include file-context feature allows the ability to use the /include command within Duo Chat and select the file to be included for context when asking Duo Chat a question.

We are moving these to the beta flag type to allow us to enable them by default.

Right now we are waiting on more adoption of the new releases for the IDE before we remove the feature flag because there is a dependency check within the client side for these flags.

• More information on that #512098 (comment 2324090312)

References

• Feature Flag Planning Issue
• Feature Flag Rollout Issue

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Before	After

How to set up and validate locally

1. Checkout update-duo-chat-include-context-ff branch

   1. git checkout update-duo-chat-include-context-ff

2. Run bundle exec rails c

3. Start gdk

   1. gdk start

4. Navigate to http://gdk.test:3000/-/graphql-explorer

5. Run the following mutation:

   query currentUser {
     currentUser {
       duoChatAvailable
       duoCodeSuggestionsAvailable
       duoChatAvailableFeatures
     }
   }

6. You should only see the include_file_context in the duoChatAvailableFeatures array in the return.

   {
     "data": {
       "currentUser": {
         "duoChatAvailable": true,
         "duoCodeSuggestionsAvailable": true,
         "duoChatAvailableFeatures": [
           "include_file_context"
         ]
       }
     },
     "correlationId": "XXXXXXXXXX"
   }