[DEVX-454]: Make Dataloader labels optional to support Data Ingestion Pipeline

[srikanthbachala20]

Why

• To support Data Ingestion Pipelines in clarifai-datautils library

How

• Made labels optional in dataloader

[github-actions]

Package	Line Rate	Health
clarifai	43%	❌
clarifai.cli	65%	➖
clarifai.client	68%	➖
clarifai.client.auth	69%	➖
clarifai.constants	100%	✔
clarifai.datasets	100%	✔
clarifai.datasets.export	80%	✔
clarifai.datasets.upload	75%	➖
clarifai.datasets.upload.loaders	37%	❌
clarifai.models	100%	✔
clarifai.modules	0%	❌
clarifai.rag	72%	➖
clarifai.runners	9%	❌
clarifai.runners.models	16%	❌
clarifai.runners.utils	57%	➖
clarifai.schema	100%	✔
clarifai.urls	80%	✔
clarifai.utils	77%	➖
clarifai.utils.evaluation	67%	➖
clarifai.workflows	94%	✔
Summary	60% (3845 / 6357)	➖

Minimum allowed line rate is 50%