Some bugs in the GranD_ReferringSegm_ds.py

[xandery-geek]

Hello, I find there may be several bugs in the GranD_ReferringSegm_ds.py file. Such as:

• undefined argument max_gt_per_img in the GrandReferSegmDataset
• the incorrect implementation for the create_conversations method
• some typos, like data_masks = data_item['maks'] which should be data_masks = data_item['masks']

I would greatly appreciate it if you could address and rectify these concerns, followed by thorough testing of the code at your earliest convenience. Thank you!