fix: Raise suitable error on unsupported SQL set op syntax

[alexander-beedie]

We don't support the ALL modifier for EXCEPT and INTERSECT set ops in the SQL interface (yet - I know how we can add this, and plan to do so in the near future).

Until this support is implemented we need to make sure we raise a suitable error instead (ALL already did this, but the ALL BY NAME qualifier was sneaking through):

Example

import polars as pl

df1 = pl.DataFrame({"n": [1, 1, 1, 2, 2, 2, 3]})
df2 = pl.DataFrame({"n": [1, 1, 2, 2]})

pl.sql("SELECT * FROM df1 EXCEPT ALL BY NAME TABLE df2")
# SQLInterfaceError: 'EXCEPT ALL BY NAME' is not supported

Was previously returning (incorrectly) the same result as EXCEPT BY NAME.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.22%. Comparing base (a284174) to head (304d953).
Report is 14 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18205      +/-   ##
==========================================
- Coverage   80.23%   80.22%   -0.01%     
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  Files        1500     1500              
  Lines      198871   198871              
  Branches     2837     2837              
==========================================
- Hits       159556   159550       -6     
- Misses      38788    38794       +6     
  Partials      527      527              

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