World Rugby would have sold the 'exclusive' rights at a premium to the broadcaster, by the government enacting that legislation they have in effect rendered the previous contract void and the initial broadcaster wouldn't be required to pay the money or World Rugby would be required to pay the money back.
If the Fiji Government wishes to add 7's Rugby to an anti-siphoning list then it should have been done with in-effect from the completion of current broadcast agreements, behaviour like this makes operating in Fiji risky business, no company wants to run a business or sign a contract in a country where the military regime undertakes rogue behaviour like this.
It would be like the Australian Government forcing Foxtel to share its 2016 Super Rugby footage with ABC for no financial remuneration. Yeah fans might celebrate in the short term but it severely devalues the deal and means the next broadcast agreement would be worth barely anything.