Time Element Step

Problem/Motivation

When selecting 5 minutes as a step for the Time element it only gives 1 minute steps as the code shows below.

time:
      '#type': time
      '#title': Time
      '#description': 'Enter pick-up time using the time picker.'
      '#default_value': '08:00'
      '#title_display': attribute
      '#description_display': invisible
      '#size': '50'
      '#flex': '5'
      '#admin_title': 'Time data'
      '#timepicker': true
      '#step': '30'

whereas selecting 10 minute steps gives 10 minute steps as below.

    time:
      '#type': time
      '#title': Time
      '#description': 'Enter pick-up time using the time picker.'
      '#default_value': '08:00'
      '#title_display': attribute
      '#description_display': invisible
      '#size': '50'
      '#flex': '5'
      '#admin_title': 'Time data'
      '#timepicker': true
      '#step': '600'

Proposed resolution

Correct the code to give 5 minutes a value of 300.