Is the 5% monthly deduction from the salary to support needy families and the children of martyrs in Palestine considered Zakat al-mal, or does the annual Zakat not lapse thereby?

For Zakat (definition), it is a condition that it be given with the intention [of Zakat] and that it be disbursed to its rightful recipients mentioned in Surah (definition) At-Tawbah (definition) (verse 60). So, if you intended this money to be Zakat and it was placed in its rightful channels, then it is permissible to count it as Zakat. However, if you did not intend it as Zakat, or if it was not placed in its rightful channels, or if it was taken from you by force, then it does not count as Zakat.