fix(cache): coerce schema_cache_timeout to None

[cemremengu]

SUMMARY

Fixes #21827

When a database is created schema_cache_timeout property is set to empty string by default inside extra_json (or at least this is the case for older versions). This leads to the following error when calling get_all_schema_names which exptects an optional integer. This PR fixes this error.

redis.exceptions.ResponseError: value is not an integer or out of range

Additionally, these params don't seem to be used in get_all_schema_names. So maybe the best course is to remove them all together.

TESTING INSTRUCTIONS

Without this, the SQL Lab shows an error when fetching schemas

[codecov]

Codecov Report

Merging #23157 (077417e) into master (871cab8) will decrease coverage by 0.79%.
The diff coverage is n/a.

❗ Current head 077417e differs from pull request most recent head 750ee48. Consider uploading reports for the commit 750ee48 to get more accurate results

@@            Coverage Diff             @@
##           master   #23157      +/-   ##
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- Coverage   67.45%   66.67%   -0.79%     
==========================================
  Files        1898     1898              
  Lines       73111    73111              
  Branches     7952     7952              
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- Hits        49320    48744     -576     
- Misses      21755    22331     +576     
  Partials     2036     2036              

Flag	Coverage Δ
hive	?
mysql	?
postgres	?
presto	52.74% <ø> (ø)
python	80.69% <ø> (-1.64%)	⬇️
sqlite	77.01% <ø> (ø)
unit	52.59% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
superset/databases/api.py	85.60% <ø> (-5.92%)	⬇️
superset/datasets/commands/update.py	25.00% <0.00%> (-69.05%)	⬇️
superset/datasets/commands/bulk_delete.py	33.33% <0.00%> (-53.34%)	⬇️
superset/datasets/columns/commands/delete.py	44.11% <0.00%> (-52.95%)	⬇️
superset/datasets/metrics/commands/delete.py	44.11% <0.00%> (-52.95%)	⬇️
superset/sql_validators/postgres.py	50.00% <0.00%> (-50.00%)	⬇️
superset/datasets/commands/delete.py	48.57% <0.00%> (-48.58%)	⬇️
superset/datasets/commands/refresh.py	43.75% <0.00%> (-43.75%)	⬇️
superset/datasets/dao.py	52.89% <0.00%> (-38.41%)	⬇️
superset/datasets/commands/duplicate.py	53.24% <0.00%> (-37.67%)	⬇️
... and 33 more

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[Antonio-RiveroMartnez]

LGTM!

[Antonio-RiveroMartnez]

When it comes to the removal of the cache_timeout, it is being accessed by the decorator:

superset/superset/models/core.py

Line 693 in 750ee48

@cache_util.memoized_func(