feat: add custom check to prevent is with enums

[glevco]

Motivation

Using is to compare values with enums is dangerous because it's possible valid values are not actually enum options. For example, 2 == TokenVersion.FEE returns True, but 2 is TokenVersion.FEE does not. This is specially dangerous when there's deserialization involved, because we have to make sure the raw value is converted to the enum, which is not always enforced by mypy.

Acceptance Criteria

• Add line number to all grep custom checks.
• Create a new custom check to catch usages of is when comparing with enums.
• Update all usages to use == instead of is.

Checklist

• If you are requesting a merge into master, confirm this code is production-ready and can be included in future releases as soon as it gets merged

[github-actions]

Bencher Report

Branch	feat/prevent-is-enum
Testbed	ubuntu-22.04

Click to view all benchmark results

Benchmark	Latency	Benchmark Result minutes (m) (Result Δ%)	Lower Boundary minutes (m) (Limit %)	Upper Boundary minutes (m) (Limit %)
sync-v2 (up to 20000 blocks)	📈 view plot 🚷 view threshold	1.98 m (+14.38%) Baseline: 1.73 m	1.56 m (78.68%)	2.08 m (95.32%)

🐰 View full continuous benchmarking report in Bencher

[codecov]

Codecov Report

❌ Patch coverage is 65.00000% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.02%. Comparing base (6ea3dc1) to head (48b560f).
⚠️ Report is 4 commits behind head on master.

Files with missing lines	Patch %	Lines
hathor/p2p/sync_v2/streamers.py	37.50%	4 Missing and 1 partial ⚠️
hathor/transaction/storage/transaction_storage.py	20.00%	1 Missing and 3 partials ⚠️
hathor/transaction/resources/mempool.py	0.00%	2 Missing and 1 partial ⚠️
hathor/indexes/rocksdb_utxo_index.py	66.66%	0 Missing and 2 partials ⚠️
hathor/nanocontracts/runner/runner.py	33.33%	0 Missing and 2 partials ⚠️
hathor/p2p/sync_version.py	0.00%	0 Missing and 2 partials ⚠️
hathor/transaction/resources/graphviz.py	0.00%	0 Missing and 2 partials ⚠️
hathor/websocket/streamer.py	33.33%	0 Missing and 2 partials ⚠️
hathor/builder/builder.py	0.00%	0 Missing and 1 partial ⚠️
hathor/dag_builder/default_filler.py	85.71%	0 Missing and 1 partial ⚠️
... and 4 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1450      +/-   ##
==========================================
+ Coverage   85.97%   86.02%   +0.05%     
==========================================
  Files         434      436       +2     
  Lines       33829    33929     +100     
  Branches     5315     5299      -16     
==========================================
+ Hits        29083    29188     +105     
+ Misses       3697     3694       -3     
+ Partials     1049     1047       -2     

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