I want to know if parking your 2 wheeler on side stand after a long ride would cause any harm to the engine parts in the sense that the oil from the oil pan would be moved to the other part due to gravity which could leave some parts of the engine which is still very hot without oil and could cause oxidation of those parts.Is this true?
No. The only difference in oil when the bike is on it's sidestand compared to being level (whether it's running or not) is where the extra oil in the pan is located. Straight up and down and it will be even across the entire pan. On it's sidestand, it will pool to the side the sidestand is located on (usually the left).
The change in location of oil in the pan doesn't have an affect on anything. As long as your oil is filled to the proper level, it will still get picked up by the oil pump and circulated through the system. The internal components of the engine which you should really be concerned about getting oil aren't affected by the lean of the bike.