[🔨 style]: consider adding `number-leading-zero` rule to stylelint config

[ala-n]

As an ESL contributor, I recomend to consider adding number-leading-zero rule to stylelint config.

As for right now we use both options with leading zero and without leading zero. Expect the style guide to be consistent across project files.

Expected style:

• no leading zero .01em

Originally posted by @dshovchko in https://github.com/exadel-inc/esl/pull/1119#discussion_r928635379