Handle char attribute "holes" in Terminal History lines

Previous implementation doesn't care about characters that are not
covered by attributes run length array elements - so the attributes of
the next run array element was taken instead of default one on the
HistoryBuffer::GetTerminalLine() call. Note that this was the case of
"holes" in run array but not the characters after the end of run array
elements.

src/apps/terminal/HistoryBuffer.cpp

@@ -88,7 +88,11 @@ HistoryBuffer::GetTerminalLineAt(int32 index, TerminalLine* buffer) const
 	for (int32 i = 0; i < line->byteLength;) {
 		// get attributes
 		if (charCount == nextAttributesAt) {
-			if (attributesRunCount > 0) {
+			if (charCount < attributesRun->offset) {
+				// the "hole" in attributes run
+				attributes = 0;
+				nextAttributesAt = attributesRun->offset;
+			} else if (attributesRunCount > 0) {
 				attributes = attributesRun->attributes;
 				nextAttributesAt = attributesRun->offset
 					+ attributesRun->length;