fix: Don't encode URLs for mamba env export --explicit

[maresb]

The URLs in the resulting explicit lockfile should ideally not be encoded, although they will not break Conda once conda/conda#14481 is released.

Reference: #3737, but this doesn't address the main issue there, which has to do with mamba create --json. This is instead about mamba env export --explicit

Test case:

micromamba env create --json --channel conda-forge --prefix=/tmp/x264 x264
micromamba env export --explicit --prefix=/tmp/x264

Note that no fix is necessary for mamba env export --json since there are no URLs in the output:

micromamba env export --json --prefix=/tmp/x264

{
  "channels": [
    "conda-forge"
  ],
  "dependencies": [
    "_libgcc_mutex=0.1=conda_forge",
    "_openmp_mutex=4.5=2_gnu",
    "libgcc=14.2.0=h77fa898_1",
    "libgcc-ng=14.2.0=h69a702a_1",
    "libgomp=14.2.0=h77fa898_1",
    "x264=1!164.3095=h166bdaf_2"
  ],
  "name": "",
  "prefix": "/tmp/x264"
}