“Now, nearly 10 months into his presidency, some of Mr. Biden’s most loyal contributors and top fund-raisers are feeling neglected if not outright cast aside, according to more than 30 interviews with Democratic donors, fund-raisers and the operatives who work with them. With the loss of the Virginia governorship this week making plain the darkening political climate for Democrats, the White House has accumulated precious little good will among some of the party’s most important financiers.