Yes, please provide a license file if you created the font. From flutter.dev/clock:
Your Submission’s code must be licensed under an appropriate open source license (for code, BSD aka University of California license, MIT license or Apache 2.0 license are recommended; for assets, CC BY 4.0 license or Apache 2.0 license are recommended; for fonts, OFL license is recommended).
Do i have to provide a license for a self made font?