Use allowlist to filter ActiveSupport breadcrumbs' data

[st0012]

Since the number of potentially hard-to-serialise data is growing, we should use allowlist to filter the data.

This should properly resolve #1183

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (75aa456) 83.23% compared to head (29854b9) 83.23%.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2048   +/-   ##
=======================================
  Coverage   83.23%   83.23%           
=======================================
  Files         119      119           
  Lines        5662     5662           
=======================================
  Hits         4713     4713           
  Misses        949      949           

Impacted Files	Coverage Δ
...b/sentry/rails/breadcrumb/active_support_logger.rb	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[st0012]

The failures are caused by latest Rails changes. I will open another PR to address it.

[st0012]

@sl0thentr0py Once this and #2036 is merged, I'd like to release v5.10.0. WDYT?

[st0012]

@sl0thentr0py I've fixed conflicts in this PR, would you mind giving it a look?

[sl0thentr0py]

@st0012 do you think we can remove this line now?

sentry-ruby/sentry-ruby/lib/sentry/breadcrumb.rb

Line 57 in 6196cec

::JSON.parse(::JSON.generate(@data))

[st0012]

@sl0thentr0py Probably not because users could still accidentally add data that's not serialisable, which we'd want to spot early with serialized_data

[sl0thentr0py]

ok let's keep it in for now, but I would actually prefer to get rid of that eventually because ideally there should be just one large JSON serialization step in client/transport. We can make it clearer in the docs/docstrings what people should pass into data.