Expose image property utilities for on-the-fly image statistics

[pavansai018]

Summary

This PR exposes lightweight, public get_* utility functions for computing image statistics (e.g. entropy, brightness, blurriness, aspect ratio) directly from in-memory PIL.Image objects.
These utilities internally reuse existing logic in image_property.py and do not duplicate any implementation.

Fixes: #210

Motivation

CleanVision currently computes image statistics only as part of dataset-wide issue detection (Imagelab + IssueManager). However, users may want to compute the same statistics:

• for a single image
• on in-memory images (e.g. API inputs, streaming data)
• without creating a dataset or writing images to disk

This PR addresses that need by exposing a small, stable utility API, as discussed in #210.

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What this PR does

• Adds get_* helper functions (e.g. get_entropy, get_brightness, get_blurriness) to image_property.py
• Each function is a thin wrapper around existing, tested internal methods
• Exposes these functions via cleanvision.utils for easy access
• Does not introduce new files or duplicate logic
• Does not modify any existing dataset or issue-detection behavior

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Example Usage

from cleanvision.utils import (
    get_entropy,
    get_brightness,
    get_blurriness,
    get_aspect_ratio,
)

entropy = get_entropy(image)          # PIL.Image
brightness = get_brightness(image)
blurriness = get_blurriness(image)
aspect_ratio = get_aspect_ratio(image)