fix(datatypes): convert UUIDs to strings

[cpcloud]

Fixes #8261.

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[cpcloud]

Confirming this fixes the repr:

In [3]: from ibis.interactive import *

In [4]: con = ibis.duckdb.connect()

In [5]: con.sql("select uuid()")
Out[5]:
┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃ uuid()                               ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│ uuid                                 │
├──────────────────────────────────────┤
│ 46bdc7b4-152c-43b7-8f8a-8d136a8cc7dd │
└──────────────────────────────────────┘

[NickCrews]

This looks good, thanks @cpcloud !

Assuming that we don't want to actually ship a pyarrow extension type (they have a uuid example there)?

[jcrist]

Nice fix

[cpcloud]

This looks good, thanks @cpcloud !

Assuming that we don't want to actually ship a pyarrow extension type (they have a uuid example there)?

Eventually maybe, but not in this PR :)

[cpcloud]

Extension types run the risk of creating type fiefdoms, and that's not good for ibis because we have to interact with downstream systems. Placing a burden on them to understand our PyArrow extension types is asking quite a lot.