Client locks up calculating blurhash

[turt2live]

Makes it really hard to type a caption while the blurhash is being calculated

[germain-gg]

This appears to be a duplicate of #17890 and has potentially been fixed by matrix-org/matrix-react-sdk#6329

Let me know whether this has fixed the problem you're facing

[t3chguy]

that PR only fixed rendering performance, not the performance issue when calculating the blurhash during sending in the first place