✨ คำตอบที่ดีที่สุด ✨
"inverview" is indeed countable (可算). If you want to express a general truth, you're talking about a general (=non-specific) job interview. So you should use "a".
You can use this experience at a job interview.
If you are having a conversation about a specific job interview, you can use "the".
Alice: I have a job interview tomorrow. Should I mention that I worked as a lifeguard?
Rabbit: Yes, you can mention this experience at the interview.
Thank you!!!