Functions with show: false are still visible in dbt docs (v1 and v2)

### Describe the bug
Functions configured with `show: false` are still visible in the generated dbt documentation. After running dbt docs generate (and serving the docs with dbt docs serve), functions marked as hidden continue to appear in the Functions section. According to the documentation, the show setting is available for the functions:
https://docs.getdbt.com/reference/function-properties?version=2.0&name=Fusion

### Steps To Reproduce
1. Define a function with the properties `show: false`:
```
functions:
- name: my_hidden_function
description: "Internal function"
config:
docs:
show: false
```
2. Run: `dbt docs generate` (on v2: `dbt compile --write-catalog` & `dbt compile --write-index`) & `dbt docs serve`
3. Open the generated documentation and navigate to the Functions section.
4. Observe that my_hidden_function is still visible.

### Expected behavior
Functions configured with show: false should not appear in the generated documentation.

### Screenshots and log output
dbt versions used:
- v1: dbt-core=1.11.12 & dbt-snowflake=1.11.6
- v2: dbt-core=v2.0.0-alpha.4 & dbt-snowflake=v1.12.0b1

Reproduce the issue with a function configured with docs.show: false, then run dbt docs generate and dbt docs serve, or the listed v2 compile commands. Trace how the Functions section receives and renders generated catalog data, and verify that hidden functions no longer appear for both v1 and v2 behavior.

Written by the indexing model from the issue text.