Set model instructions in java sample for Realtime API

[andreasjl]

Purpose

The java sample for Realtime API does not return any audio with the current model. Fix this by telling the model explicitly in the instructions to return audio.

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

What kind of change does this Pull Request introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

• Get the code

git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
npm install

• Run the Main class from java/console

What to Check

Verify that the following are valid

• The model responds with audio

Other Information