Is a prosecution's claim that a defendant's lawyer is 'likely to be a necessary witness' an 'actual conflict' or 'serious potential conflict' overriding the defendant's Sixth Amendment right to counsel?

Questions Presented 1) Is a prosecution’s claim that a defendant’s lawyer is “likely to be a necessary witness” at trial an “actual conflict” or “a serious potential conflict” that overrides the defendant’s right to counsel of his choice under the Sixth Amendment and Wheat v. United States, 486 U.S. 153, 164, 108 S. Ct. 1692, 100 L. Ed. 2d 140 (1988)? 2) What standard must a district court employ in deciding whether to grant or deny a criminal defense attorney’s motion to withdraw from representation, and what standard should a court of appeals employ to review such decisions?