What is the test for determining whether a cause of action alleges both protected activity and unprotected activity?

Where, as here, a cause of action alleges both activity protected under section 425.16, subdivision (e) and unprotected activity, we apply the " 'principal thrust or gravamen' test." (Club Members for an Honest Election v. Sierra Club (2008) 45 Cal.4th 309, 319 (Club Members).) "The 'principal thrust or gravamen' test has been used to determine whether an action fits within the scope of the anti-SLAPP protection provided by section 425.16 when a pleading contains allegations referring to both protected and unprotected activity. [Citation.]" (Ibid.)