Fixed: Fix CSI Delete Ps Column(s) (DECDC)

Firstly, `TerminalBuffer.blockSet()` was throwing the exception since `sx + w > mColumns` which was technically passed by TerminalEmulator.blockClear()`. Actual value would be `mCursorRow + columnsToMove + columnsToDelete > mColumns`.

Secondly, the call to `blockClear()` should not be needed since it the `blockCopy()` would overwrite the columns to be deleted on copy.

Run `printf "\e['~"` to delete 1 column and `printf "\e[3'~"` to delete 3 columns. Run `printf "\e[3'}"` to insert 2 columns.

java.lang.IllegalArgumentException: Illegal arguments! blockSet(78, 0, 1, 30, 32, 56, 30)
at com.termux.terminal.TerminalBuffer.blockSet(TerminalBuffer.java:397)
at com.termux.terminal.TerminalEmulator.blockClear(TerminalEmulator.java:2035)
at com.termux.terminal.TerminalEmulator.processCodePoint(TerminalEmulator.java:799)

terminal-emulator/src/main/java/com/termux/terminal/TerminalEmulator.java

@@ -796,7 +796,6 @@ public void processCodePoint(int b) {
  int columnsToDelete = Math.min(getArg0(1), columnsAfterCursor);
  int columnsToMove = columnsAfterCursor - columnsToDelete;
  mScreen.blockCopy(mCursorCol + columnsToDelete, 0, columnsToMove, mRows, mCursorCol, 0);
- blockClear(mCursorRow + columnsToMove, 0, columnsToDelete, mRows);
  } else {
  unknownSequence(b);
  }