“The applicant did not respond to this request to admit by either by the original 21-day deadline or the judicially extended deadline to 21-days after December 4, 2019. Where a party fails to respond to a request to admit prior to trial and prior to trial fails to seek leave to withdraw his deemed admissions, the party should not be permitted to withdraw them: see Jama v. Basdeo, 2020 ONSC 2922, at paras. 16-21.”