Attorney’s fees — Proposal for settlement — Contractual fee agreement — Trial court erred in denying attorney’s fees pursuant to section 768.79 on the basis that fee provision in lease agreements prevented simultaneous award of attorney’s fees under the statute where fee provision in leases did not explicitly waive attorney’s fees available per statute, statute imposes a penalty, and plain language of statute makes attorney’s fee award mandatory if all requirements are met — Ambiguity — Trial court erred in determining that offers of settlement were ambiguous because it could not determine whether the offers should be aggregated for the purposes of comparison to the judgment where aggregating of offers of settlement for purpose of determining attorney’s fees cannot be tolerated under strict construction of statute