Intent is irrelevant to absolute immunity. That is what distinguishes qualified immunity (such as what a cop enjoys) from from absolute immunity (such as what a prosecutor, grand juror, or judge enjoys). Qualified immunity is subject to exceptions for bad faith or malice. Absolute immunity is not.
The law grants prosecutors absolute immunity from civil liability for instituting a prosecution, presenting their case to a grand jury or court, or anything else “intimately associated with the judicial phase of the criminal process.”
Presenting a bill of indictment to a grand jury is plainly within the scope of a prosecutor’s absolute immunity. Thus, if all the prosecutor is being sued for is instituting a prosecution, which is all that it appears the prosecutor did here, then it makes no difference whether why she did so, even if it was with the specific, malicious intent to violate civil rights.
You may disagree with this doctrine (and many people do), but it is the law in Texas and in most other states, and it has been held by the US Supreme Court to be the law applicable in 1983 suits since Imbler v. Pachtman in 1976.
Tell all that to those Mississippi officials in prison.