Donors of Democratic presidential nominee Kamala Harris are reportedly pushing her to give up her support of a plan that would tax wealthy Americans and increase federal revenue by $5 trillion over 10 years. Last week, the vice president quietly unveiled her proposal to increase taxes. Notably, no one earning less than $400,000 would see their taxes increase, according to The New York Times. President Joe Biden proposed — and Harris supported — a plan that would tax investment gains on Americans worth $100 million or more if they haven’t sold the stocks, bonds or other assets that have appreci…