united-states california
You can take as many as you have permission to.
As with many crimes, theft or larceny has a mens rea component: the same physical action might or might not be criminal depending on if it is accompanied by criminal intentions. The mens rea component of theft typically includes intent to deprive the owner of the property permanently (or sometimes, just for some significant amount of time). Therefore, mistaken belief of rightful ownership is a defense to theft (per CALCRIM No. 1800. Theft by Larceny (Pen. Code, § 484) Judicial Council of California Criminal Jury Instructions (2023 edition)).
If you genuinely believed you had permission to take all the mints, you would not be guilty of the crime of theft. In contrast, if you took all the mints without having permission and with the knowledge that you did not have permission to take them all, that would be a crime.
Laws vary from state to state but it is common to have a statutory distinction between a felony and misdemeanor based on the value of what is being stolen (or if it falls in some special category such as firearms). In California, something worth $950 or less (which presumably covers a bowl of mints) falls into the category of petty theft (a misdemeanor). Furthermore, prosecutorial discretion is obviously relevant in practice.