University does not explicitly request either a motivational letter or recommendation letters
Finnish students are typically granted a permission to study the Bachelor's and Master's degrees both with a single application after completing upper secondary school. Therefore, there is practically no culture of writing recommendation letters before the PhD level, and even then it is kind of a rare thing.
The situation is only slightly different for foreign students, since the universities want to make sure they are recruiting good students, given that there are no tuition or other fees except the compulsory 100€ per year for almost all-inclusive dental and other health care.
In the specific page you link to, it is stated that

Admission will be based on the grade, applicability of the previous degree, the motivation letter, and the possible preliminary assignment which is used to assess the applicability of the applicant’s previous competence.
The applicant must enclose with his or her application a copy of the diploma, an official transcript of completed studies and a motivation letter describing the applicant’s personal goals and reasons for applying.

Therefore, it would appear on a first look that no recommendation letters are sought, which is what I would expect.
The comments asked for additional clarification. For example, the Faculty of Social Sciences of University Helsinki writes

Please, submit only documents required. Any additional documents like articles written by an applicant, recommendation letters etc. will not be included for evaluation of an application. If a research plan (including references) is longer than 5 pages, the extra pages will be cut out.

in their PhD application guidelines. In most cases, the system here is just very different.
Anyway: better safe than sorry. Ask them what to do.