fix(geometry): make output handling robust to text or bytes

[cpcloud]

Fixes some issues discovered while attempting to address #10209. Will expand with more detail later today.

[cpcloud]

BigQuery is passing:

cloud in 🌐 falcon in …/ibis on  bq-geom is 📦 v9.5.0 via 🐍 v3.12.7 via ❄️  impure (ibis-3.12-env)
❯ pytest -m bigquery -n auto --dist loadgroup --snapshot-update -q
bringing up nodes...
.xxxxxxxxx.xxxxxxxxxxxxxxxxxxxxxxxxxx.xxxxxxxxxxxxx.xxxxxxxxxxxxxxxxxxx.xxxxxx.xxxxxx.xxxxxxxxx.xxxxxxxxxxxx.xxxsssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssxxx.xx.........xxxxxx.x......xx.x......xx...x.....x....s........x.........s............x...x..............x......s...................................x...........xxx..x..x........ [ 17%]
sssssssssssssssss.ssss..x....x.......x....................x......x.......xx......x...........x....................................................x.........x....x........x.........x.....x.............x....x...x......x.........xxx.x..................xx..........x...........x.................x.xx.............x.....x..x..x.xxx....x......x.....x...x.........xx................x.x.......x.x.x [ 34%]
xx..........................sx...xxx.x.s.........x.x......s...x....x....x...x.x..........s............x....x.......x.xxxx..x.......x............x........x..xx......x.x.......x.x...x......x.x..x....xxx......x.x.xx........x....xx...x.......xxx.........x..x...........x...x.x....x.xxx.x....xxx.x..xx..xxx..xxx...xx..x.x.xxxxxx.x.x.x.......xx..xx.........xxx..xx......x.......x.....x.......... [ 51%]
..x.............................xx.........................................................x...............x................x.......s..............x..........x............xx.x...x..x..x....x...x.xx..x................xxX......x....x.........x...xx......x.x....x.x.xXx......X..x...x..X..x.x...x..x...x...xx..xx......x.x..............xx..x.......x.x..................x....................xx.. [ 68%]
....................x.....xx..x........x.xx.......x............x.....x...............................x............x.........x.x.....x.......x.x........x.......xx.....x.............xs......xx...........s.......s....s.................................x........................................x.......x................................................x.......................................... [ 86%]
.....x.................................................................x......................................................................................................................................x.........................................x.................................................................                                                                            [100%]
1762 passed, 132 skipped, 361 xfailed, 4 xpassed in 247.51s (0:04:07)