Remove unreachable code in SGR handling 100

The implementation seems to be wrong. This looks like a remnant left over from
term.js before bright SGR was implemented.

Author: Tyriar

src/common/InputHandler.ts

@@ -2713,12 +2713,6 @@ export class InputHandler extends Disposable implements IInputHandler {
         attr.extended = attr.extended.clone();
         attr.extended.underlineColor = -1;
         attr.updateExtended();
-      } else if (p === 100) { // FIXME: dead branch, p=100 already handled above!
-        // reset fg/bg
-        attr.fg &= ~(Attributes.CM_MASK | Attributes.RGB_MASK);
-        attr.fg |= DEFAULT_ATTR_DATA.fg & (Attributes.PCOLOR_MASK | Attributes.RGB_MASK);
-        attr.bg &= ~(Attributes.CM_MASK | Attributes.RGB_MASK);
-        attr.bg |= DEFAULT_ATTR_DATA.bg & (Attributes.PCOLOR_MASK | Attributes.RGB_MASK);
       } else {
         this._logService.debug('Unknown SGR attribute: %d.', p);
       }