dependencies: Stop using github.com/apparentlymart/go-dump

This upstream library (which I wrote, independently of my work on OpenTofu)
came about because "go-spew" tended to produce unreadable representations
of certain types commonly used in OpenTofu, whereas "go-dump" is really
just a pretty-printer for whatever a type might produce when formatted
using the %#v verb in package fmt.

Over time the uses of this seem to have decreased only to some leftover
situations where we wanted to pretty-print a cty.Value in a test, but
we already depend on go-cty-debug that has a more specialized
implementation of that behavior and so switching the few remaining callers
over to that allows us to remove one dependency.

(And, FWIW, that upstream dependency is effectively unmaintained; I don't
know of any callers of it other than OpenTofu itself, and after merging
this even OpenTofu won't depend on it anymore.)

Signed-off-by: Martin Atkins <mart@degeneration.co.uk>

go.sum

@@ -144,8 +144,6 @@ github.com/antchfx/xpath v1.1.10/go.mod h1:Yee4kTMuNiPYJ7nSNorELQMr1J33uOpXDMByN
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/apparentlymart/go-cidr v1.1.0 h1:2mAhrMoF+nhXqxTzSZMUzDHkLjmIHC+Zzn4tdgBZjnU=
 github.com/apparentlymart/go-cidr v1.1.0/go.mod h1:EBcsNrHc3zQeuaeCeCtQruQm+n9/YjEn/vI25Lg7Gwc=
-github.com/apparentlymart/go-dump v0.0.0-20190214190832-042adf3cf4a0 h1:MzVXffFUye+ZcSR6opIgz9Co7WcDx6ZcY+RjfFHoA0I=
-github.com/apparentlymart/go-dump v0.0.0-20190214190832-042adf3cf4a0/go.mod h1:oL81AME2rN47vu18xqj1S1jPIPuN7afo62yKTNn3XMM=
 github.com/apparentlymart/go-shquot v0.0.1 h1:MGV8lwxF4zw75lN7e0MGs7o6AFYn7L6AZaExUpLh0Mo=
 github.com/apparentlymart/go-shquot v0.0.1/go.mod h1:lw58XsE5IgUXZ9h0cxnypdx31p9mPFIVEQ9P3c7MlrU=
 github.com/apparentlymart/go-textseg/v15 v15.0.0 h1:uYvfpb3DyLSCGWnctWKGj857c6ew1u1fNQOlOtuGxQY=