quotient_ideal on FreeAlgebra quotient

[asbuch]

Describe the bug
quotient_ideal(Q) is not defined when Q is a quotient of a FreeAlgebra.

To Reproduce

using Singular
R, (x,y) = FreeAlgebra(QQ, ["x", "y"], 6)
Q, (a,b) = QuotientRing(R, Ideal(R, x-y))
quotient_ideal(Q)  # MethodError, expected Ideal(R, x-y)

Expected behavior
Expected result: return the ideal defining Q.

Information about your setup:
julia> versioninfo()
Julia Version 1.7.3
Commit 742b9abb4d (2022-05-06 12:58 UTC)
Platform Info:
OS: Linux (x86_64-pc-linux-gnu)
CPU: 13th Gen Intel(R) Core(TM) i5-1345U
WORD_SIZE: 64
LIBM: libopenlibm
LLVM: libLLVM-12.0.1 (ORCJIT, goldmont)

julia> using Pkg; Pkg.status(mode=PKGMODE_MANIFEST)
Status /tmp/singbug/Manifest.toml
[c3fe647b] AbstractAlgebra v0.31.0
[f01c122e] BinaryWrappers v0.1.2
[1f15a43c] CxxWrap v0.13.4
[d5909c97] GroupsCore v0.4.0
[692b3bcd] JLLWrappers v1.4.1
[1914dd2f] MacroTools v0.5.10
[2edaba10] Nemo v0.35.3
[fa939f87] Pidfile v1.3.0
[21216c6a] Preferences v1.4.0
[fb686558] RandomExtensions v0.4.3
[6c6a2e73] Scratch v1.2.0
[bcd08a7b] Singular v0.18.9
[e21ec000] Antic_jll v0.201.500+0
[d9960996] Arb_jll v200.2300.0+0
[fcfa6d1b] Calcium_jll v0.401.100+0
[e134572f] FLINT_jll v200.900.7+0
[e8aa6df9] GLPK_jll v5.0.1+0
[656ef2d0] OpenBLAS32_jll v0.3.17+0
[43d676ae] Singular_jll v403.203.202+0
[f07e07eb] cddlib_jll v0.94.13+0
[1493ae25] lib4ti2_jll v1.6.10+0
[3eaa8342] libcxxwrap_julia_jll v0.9.7+3
[ae4fbd8f] libsingular_julia_jll v0.36.0+0
[0dad84c5] ArgTools
[56f22d72] Artifacts
[2a0f44e3] Base64
[ade2ca70] Dates
[f43a241f] Downloads
[7b1f6079] FileWatching
[b77e0a4c] InteractiveUtils
[b27032c2] LibCURL
[76f85450] LibGit2
[8f399da3] Libdl
[37e2e46d] LinearAlgebra
[56ddb016] Logging
[d6f4376e] Markdown
[ca575930] NetworkOptions
[44cfe95a] Pkg
[de0858da] Printf
[3fa0cd96] REPL
[9a3f8284] Random
[ea8e919c] SHA
[9e88b42a] Serialization
[6462fe0b] Sockets
[2f01184e] SparseArrays
[10745b16] Statistics
[fa267f1f] TOML
[a4e569a6] Tar
[8dfed614] Test
[cf7118a7] UUIDs
[4ec0a83e] Unicode
[e66e0078] CompilerSupportLibraries_jll
[781609d7] GMP_jll
[deac9b47] LibCURL_jll
[29816b5a] LibSSH2_jll
[3a97d323] MPFR_jll
[c8ffd9c3] MbedTLS_jll
[14a3606d] MozillaCACerts_jll
[4536629a] OpenBLAS_jll
[83775a58] Zlib_jll
[8e850b90] libblastrampoline_jll
[8e850ede] nghttp2_jll
[3f19e933] p7zip_jll