Remove legacy SORT_WIDTH spacing logic in SWT.Tree

[ShahzaibIbrahim]

Description
Since Windows 7, the sort indicator in tree columns is rendered above the column header text, whereas in Windows XP it was placed next to the text. The original SWT implementation added extra pixels (SORT_WIDTH) to the column width to make space for the indicator.

This legacy spacing logic is no longer required on modern platforms and results in unnecessary extra padding in tree columns.

Proposed Change

Remove the additional SORT_WIDTH spacing logic in Tree column rendering.

Verify that sort indicators are correctly aligned above the column text on all supported platforms (Windows 7 and newer).

[akoch-yatta]

As Tree and Table share the same UI for the sorting, we should adapt both in this ticket

[ShahzaibIbrahim]

@akoch-yatta but shouldn't we create a separate PR for both?