decimal division gives wrong answer

[kmitchener]

Describe the bug
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❯ select 10.1::decimal(5,1)/a from (values (1),(null)) as t(a);
+---------------------------+
| Float64(10.1) / t.a       |
+---------------------------+
| 10.0999999999999997902848 |
|                           |
+---------------------------+
2 rows in set. Query took 0.005 seconds.

Note also that the return type is correctly Decimal, it's just giving wrong results because it's using float internally to do the division.

❯ select arrow_typeof(10.1::decimal(5,1)/a) from (values (1),(null)) as t(a);
+----------------------------------+
| arrowtypeof(Float64(10.1) / t.a) |
+----------------------------------+
| Decimal128(26, 22)               |
| Decimal128(26, 22)               |
+----------------------------------+
2 rows in set. Query took 0.010 seconds.

To Reproduce
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Expected behavior
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This should return 10.1 and null.

Additional context
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