Friendly rivalry aside, Finland and Speden have strong formal military cooperation and even stronger informal diplomatic backchannels because of the political realities.
I personally only spent a couple of years in the military and still did multiple exercises with Sweden and Norway and stayed at Swedish bases a couple of times…there’s active cooperation.
Regardless of how openly this is spoken about in the public you can be quite confident that the high command of both countries’ militaries have agreed on strategies on how to deal with choke points in case of an offensive from the East.
While Finland is a buffer zone for Sweden, considering the nature of the adversary it is certainly in Stockholm’s best interests to assist Finland’s war efforts rather than blowing some bridges willy nilly without asking the Finns first. Especially considering that knowing our ways when it comes to guerilla defence, chances are that bridge has a shaped charge - shaped cavity already built in by the original bridge engineers, just in case