fix: make disable_plugins accept Plugin types instead of strings

[masenf]

Change disable_plugins from list[str] to list[type[Plugin]] so both plugins and disable_plugins use consistent Plugin-based types (#6150).

Strings and instances are still accepted at runtime with a deprecation warning, and normalized to the Plugin class. Environment variable support via REFLEX_DISABLE_PLUGINS continues to work through a new interpret_plugin_class_env interpreter, which interpret_plugin_env now reuses for class resolution.

Fix #6150

[codspeed-hq]

Merging this PR will not alter performance

✅ 8 untouched benchmarks

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_{Comparing claude/hopeful-merkle (e1373b6) with main (e7c3742)}

[greptile-apps]

Greptile Summary

This PR migrates disable_plugins from list[str] to list[type[Plugin]], making it consistent with the plugins field and enabling type-safe, IDE-friendly configuration. Backward compatibility is preserved through runtime normalization with deprecation warnings, and environment variable support (REFLEX_DISABLE_PLUGINS) is maintained via the new interpret_plugin_class_env helper.

Key changes:

• BaseConfig.disable_plugins type changed from list[str] to list[type[Plugin]]
• Config._normalize_disable_plugins() added to coerce legacy string/instance entries to Plugin classes with deprecation warnings
• interpret_plugin_class_env extracted from interpret_plugin_env so both class-resolution and instance-creation paths share logic
• interpret_env_var_value now dispatches type[Plugin] annotated fields to interpret_plugin_class_env
• _add_builtin_plugins updated to use class-based in checks instead of string matching
• Comprehensive tests added for all normalization paths and the new env-var interpreter

One minor issue found: an inline comment in the normalization logic incorrectly describes the conversion direction.

Confidence Score: 4/5

• Safe to merge; changes are well-tested and backward-compatible with only a minor inline comment issue.
• The PR logic is sound, all backward-compatibility paths are covered by tests, and the env-var plumbing correctly handles the new list[type[Plugin]] type. One minor style issue found: a misleading inline comment in reflex/config.py that describes the conversion direction incorrectly.
• reflex/config.py — fix misleading comment on line 356.

_{Last reviewed commit: e1373b6}

[greptile-apps]

The comment says "convert strings and Plugin subclasses to instances", but the actual logic does the opposite: it converts Plugin instances (and strings) to Plugin classes. The word "subclasses" and "instances" are swapped.

Suggested change

	# Normalize disable_plugins: convert strings and Plugin subclasses to instances.
	# Normalize disable_plugins: convert strings and Plugin instances to Plugin subclasses.