truncation error with `rtol`

[ogauthe]

using TensorKit

m1 = ones((2,2))
m2 = id(ℂ^2)

svd_trunc(m1; trunc=trunctol(;rtol=0.5))  # Ok
svd_trunc(m2; trunc=trunctol(;atol=0.5))  # Ok
svd_trunc(m2; trunc=trunctol(;rtol=0.5))  # MethodError

ERROR: MethodError: no method matching _norm(::TensorKit.SortedVectorDict{Trivial, SubArray{Float64, 1, Vector{Float64}, Tuple{UnitRange{Int64}}, true}}, ::Int64)
The function `_norm` exists, but no method is defined for this combination of argument types.

Closest candidates are:
  _norm(::Any, ::Real, ::Real)
   @ TensorKit ~/Documents/tensorkit/TensorKit.jl/src/tensors/linalg.jl:268

Stacktrace:
 [1] rtol_to_atol(S::TensorKit.SortedVectorDict{Trivial, SubArray{Float64, 1, Vector{Float64}, Tuple{UnitRange{…}}, true}}, p::Int64, atol::Float64, rtol::Float64)
   @ TensorKit.Factorizations ~/Documents/tensorkit/TensorKit.jl/src/factorizations/truncation.jl:116
 [2] findtruncated_svd
   @ ~/Documents/tensorkit/TensorKit.jl/src/factorizations/truncation.jl:189 [inlined]
 [3] truncate(::typeof(svd_trunc!), ::Tuple{…}, strategy::MatrixAlgebraKit.TruncationByValue{…})
   @ TensorKit.Factorizations ~/Documents/tensorkit/TensorKit.jl/src/factorizations/truncation.jl:65
 [4] svd_trunc!
   @ ~/.julia/packages/MatrixAlgebraKit/xv5dv/src/implementations/svd.jl:241 [inlined]
 [5] svd_trunc!
   @ ~/.julia/packages/MatrixAlgebraKit/xv5dv/src/algorithms.jl:244 [inlined]
 [6] #svd_trunc!#104
   @ ~/.julia/packages/MatrixAlgebraKit/xv5dv/src/algorithms.jl:238 [inlined]
 [7] svd_trunc!
   @ ~/.julia/packages/MatrixAlgebraKit/xv5dv/src/algorithms.jl:237 [inlined]
 [8] #svd_trunc#103
   @ ~/.julia/packages/MatrixAlgebraKit/xv5dv/src/algorithms.jl:233 [inlined]
 [9] top-level scope
   @ REPL[6]:1
Some type information was truncated. Use `show(err)` to see complete types.

julia v"1.12.1"
TensorKit v0.15.3

The issue is in the same function truncate but this seems unrelated to #313

[ogauthe]

I still get this issue with latest TensorKit - both 0.16.0 release and main at d60855e4acfc53209455f873a8105300d9aa95ff.