fix for julia 1.7

[oxinabox]

Closes #549

• Change in structured handles factorization becoming less accurate and thus finite differencing beween less accurate
• Just ups out tolerance of error
• https://github.com/JuliaDiff/ChainRules.jl/runs/4390009367?check_suite_focus=true#step:6:134

And

• Change in symmetric handles factorization becoming less accurate and thus the finite differencing escaping the domain (we possibly should fix the _fdm to point the right way though?)
• This change just makes sure our initial point is less close to boundry

[oxinabox]

I am merging this because merging without proper review seems less bad than leaving CI broken