Fix incorrect ceiling calculation in ceil_of_element_in_sorted_array.cpp

[SinghCod3r]

Description This PR resolves Issue #6832 (“Incorrect Return Value in solve Function”).

Key points • Binary-search condition corrected — now treats arr[mid] > ele as a valid ceiling candidate. • Updates pointer movement accordingly ( high = mid-1 , low = mid+1 ). • Adds guard to return -1 when no ceiling exists. • Keeps expected behavior when ele is present in the array ( ele itself is returned).

Result solve() now reliably returns the smallest element ≥ ele , fixing the previous off-by-one logic and ensuring accurate algorithm-application examples.

closes #6832