chore: Adds a tooltip for the alert's SQL input

[michael-s-molina]

SUMMARY

It's not very clear that the SQL used to create an alert should return a numeric value. When non-numeric values are returned, the error Alert query returned a non-number value is thrown when firing the alert. This PR adds a tooltip for the alert's SQL input to instruct users in advance.

Closes #26298

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

1 - Open the alert creation modal
2 - Check the displayed tooltip

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (eb65cea) 69.18% compared to head (fe2d2f6) 69.18%.
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master   #26317   +/-   ##
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  Coverage   69.18%   69.18%           
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  Files        1945     1945           
  Lines       75968    75970    +2     
  Branches     8467     8467           
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+ Hits        52557    52559    +2     
  Misses      21224    21224           
  Partials     2187     2187           

Flag	Coverage Δ
javascript	56.52% <100.00%> (+<0.01%)	⬆️

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[john-bodley]

@michael-s-molina technically it doesn't need to be numeric, i.e., it could be a string, as we use the Python float() method. Maybe something like:

... a numeric-esque value

While we're at it, should we also simply remove tooltip for the threshold value,

given that it technically doesn't need to be a double precision number, e.g., an integer will work. It seems like the input box rejects non-numerical values (excluding the period) and thus the input in already sanitized.

[michael-s-molina]

@john-bodley Applied your suggestions.