I noticed it showed up quite a bit on our production allocation
profiles. I tried to not break the interface, but in reality most
of it is private and it should only be configured through `application.config`.

main:

```
ruby 3.3.3 (2024-06-12 revision f1c7b6f435) +YJIT [arm64-darwin23]

Total allocated: 1440 bytes (18 objects)

Calculating -------------------------------------
                 tag    521.552k (± 2.0%) i/s -      2.652M in   5.087518s
```

this branch:

```
ruby 3.3.3 (2024-06-12 revision f1c7b6f435) +YJIT [arm64-darwin23]

Total allocated: 840 bytes (7 objects)

Calculating -------------------------------------
                 tag      1.070M (± 1.9%) i/s -      5.379M in   5.026878s
```

Benchmark:

```ruby
require 'bundler/inline'

gemfile(true) do
  source "https://rubygems.org"

  gem "benchmark-ips"
  gem "memory_profiler"
  gem "rails"
end

require "active_record"

ActiveRecord::QueryLogs.taggings = {
  some_handler: -> { "Handler" }
}
ActiveRecord::QueryLogs.tags = [
  :application,
  :some_handler,
  fixed_string: "fixed string",
  callback: ->(context) { "callback" },
]

ActiveSupport::ExecutionContext[:application] = "SuperApp"

ActiveRecord::QueryLogs.singleton_class.class_eval { public(:tag_content) }

ActiveRecord::QueryLogs.tag_content(:__connection__)

report = MemoryProfiler.report do
  ActiveRecord::QueryLogs.tag_content(:__connection__)
end

report.pretty_print

Benchmark.ips do |x|
  x.report("tag") { ActiveRecord::QueryLogs.tag_content(:__connection__) }
end
```