Buttons are not centered

[ildar170975]

Consider this code:

type: entities
entities:
  - type: custom:lovelace-multiline-text-input-card
    entity: input_text.test_text_255

Buttons are not centered:

Seems that the 2nd span element prevents it:

Fixed it by adding margin-top: 6px; for a flex element:

But a proper value may depend on a particular client.