It’s clearly not actionable.
You can’t use illegally and unlawfully obtain evidence.
Don't confuse constitutional law under the 4th amendment with the California statute regarding recording someone without their permission. The 4th amendment applies to governments, not individuals, to prevent the use in a criminal proceeding, or quasi-criminal proceeding (like an administrative matter)of evidence obtained in violation of the 4th amendment. Individuals, however, can obtain information any number of ways and it is not a violation of the 4th amendment, and it may later be used in a court proceeding for civil or criminal matters.
However, this statute creates a privacy right in California to not be recorded without your knowledge or consent. The law prohibits the use of such a recording in any civil or criminal proceeding. It's a little different situation than your standard 4th amendment case.