Reuse the jobs for exporting llama3.3.2-3b model.

[codereba]

I try to export the llama to Snapdragon 8 Elite X by following the guidance:
https://github.com/quic/ai-hub-apps/tree/main/apps/android/ChatApp

I run the command:
python -m qai_hub_models.models.llama_v3_2_3b_chat_quantized.export --context-length 2048 --device "Snapdragon 8 Elite QRD" --output-dir genie_bundle
After waiting many hours, the error happened, please refer to:
#154

I rerun this command:
python -m qai_hub_models.models.llama_v3_2_3b_chat_quantized.export --context-length 2048 --device "Snapdragon 8 Elite QRD" --output-dir genie_bundle

That will redo all the completed steps, that consumes a lot of time and many resources to redo the works.(many hours for 10Mbps upload speed).

This patch will check whether the jobs exist, if that's true then let user to choose whether to use them directly (because the jobs may be different in the detail, but that's not a common case).

Please note:
I think the script can ignore the quantization steps if all the jobs exist, but that changes more, I need to get your suggestion firstly before I try to do it.

The patch is tested locally, it used the submitted jobs, and download the linked models, please refer to the screen shot:

[bhushan23]

Thank you very much @codereba for this change.

We are internally also working on general caching for all LLM export and will release in next release.
Loved how you have used job summaries to cache at export level. Amazing work :)

We look forward to seeing more contributions from you :)

[codereba]

Thank you very much @codereba for this change.

We are internally also working on general caching for all LLM export and will release in next release. Loved how you have used job summaries to cache at export level. Amazing work :)

We look forward to seeing more contributions from you :)

Yes, I try to contribute more :)