Fix: omnidir.calibrate assertion failure in Python bindings (#28462)

[Sikandar1310291]

InputArrayOfArrays::type() and ::depth() don't correctly report element types when called from Python bindings. Changed to use getMat(0).type() and getMat(0).depth() to check the first element's type instead.

Affected functions:

• cv::omnidir::calibrate
• cv::omnidir::stereoCalibrate
• cv::omnidir::internal::computeJacobian
• cv::omnidir::internal::computeJacobianStereo

Fixes opencv/opencv#28462

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