using PyPlot crashes package precompilation on Julia v1.10.0-beta1

[pszufe]

[This is also cross-posted on PyPlot https://github.com/JuliaPy/PyPlot.jl/issues/572 - if it is not useful here pls close it]

Consider the following package:

(@v1.10) pkg> generate Test1
  Generating  project Test1:
    Test1\Project.toml
    Test1\src\Test1.jl

Where PyPlot has been added via Pkg.add to dependencies and Test1.jl contains

module Test1
using PyPlot
end 

In that case using Test1 (after Pkg.activate) goes into an endless loop (I pressed Ctrl+C at some point):

julia> using Test1
Precompiling Test1
  Progress [>                                        ]  0/1
  ◑ Test1 Waiting for background task / IO / timer. Interrupt to inspect
 Interrupted: Exiting precompilation...

  1 dependency had warnings during precompilation:
┌ Test1 [ddca8587-cad1-46e2-86b4-b726afea1d60]
│  [pid 7156] waiting for IO to finish:
│   TYPE[FD/PID]       @UV_HANDLE_T->DATA
│   timer              @00000228c312eca0->00000228bf815db0
└

When this is run on a fresh Julia installation it seemed that it additionally tries to install matplotlib via Conda (regardless of the fact that it is already present due to PyPlot being built earlier).

Tested on Julia 1.10 beta1, Windows11 as well Linux by myself and @giordano