Kahn won the next election including outer boroughs that were affected by the ULEZ expansion
https://metro.co.uk/2024/05/04/map-reveals-london-mayor-elec...
What the election map on your article shows is a bunch of outer boroughs ("some"?) choosing the Tory candidate over the Labour one, there just weren't enough of them overall. Elections aren't usually single-issue, and there's probably enough value in reelecting Kahn (or his opponents are odious enough), that forcing a large number of people to set their money on fire didn't entirely wreck his chances.
But you'll note that lessons have been learned. Back in 2019, the IEA were demanding the complete ban of gas boilers by 2026. The government never adopted such a policy, it's only too well aware at how much needless cost and effort it'd put the entire country through by making 80% of households throw out their heating system and buy another one, for the sake of the planet. So that's why the closest the government got to that was proposing in 2020/2021 maybe banning them by 2035. And now? The government is reassuring people that it won't ban gas boilers; not in 2026, not in 2035, not in 2050, not ever. It saw what banning cars in London kicked off. It doesn't want that for itself.