chore: replace `recover_data` with `recover_polynomial_coeff`

[kevaundray]

Previously when we were solely recovering cells, we need the reconstructed data/all of the cells.

Now that we only do reconstruction in order to call compute_cells_and_kzg_proofs, we can skip computing the cells and just return the polynomial that when evaluated will give you the extended blob.

[kevaundray]

Would wait for #3819 as it makes that method even simpler