fix: return ocr coordinates points as tuple (#1219)
The `add_pytesseract_bbox_to_elements` returned the
`metadata.coordinates.points` as `Tuple` whereas other strategies
returned as `List`. Make change accordingly for consistency.
Previously:
```
element.metadata.coordinates.points = [
(x1, y1),
(x2, y2),
(x3, y3),
(x4, y4),
]
```
Currently:
```
element.metadata.coordinates.points = (
(x1, y1),
(x2, y2),
(x3, y3),
(x4, y4),
)
```
