[Bug]: Using 'Hide Text' setting with Invidious throws

### Guidelines

- [x] I have encountered this bug in the [latest release of FreeTube](https://github.com/FreeTubeApp/FreeTube/releases).
- [x] I have encountered this bug in the [official downloads of FreeTube](https://github.com/FreeTubeApp/FreeTube#official-downloads). **The only official downloads are from the [https://freetubeapp.io](https://freetubeapp.io/#download) website, the [FreeTubeApp/FreeTube GitHub repository](https://github.com/FreeTubeApp/FreeTube/releases) and the [io.freetubeapp.FreeTube flatpak](https://flathub.org/en/apps/io.freetubeapp.FreeTube) from Flathub.**
- [x] I have [searched the issue tracker for **open and closed** issues](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aissue+sort%3Arelevance-desc) that are similar to the bug report I want to file, without success.
- [x] I have searched the [documentation](https://docs.freetubeapp.io/) for information that matches the description of the bug I want to file, without success.
- [x] This issue contains only one bug.
- [x] I have read and agree to follow the [rules](https://docs.freetubeapp.io/community/rules/).

### Describe the bug

1. Go to Settings > Distraction Free and set a value inside 'Hide [...] Text' setting
2. Go to https://www.youtube.com/channel/UC8butISFwT-Wl7EV0hUK0BQ
3. Go to 'Podcasts' tab
4. Observe `renderer.js:2 TypeError: Cannot read properties of undefined (reading 'includes')`

### Expected Behavior

No error

### Issue Labels

feature stopped working

### FreeTube Version

v0.25.3-nightly-7764 Beta

### Operating System Version

Bazzite

### Installation Method

.AppImage

### Primary API used

Invidious API

### Last Known Working FreeTube Version (If Any)

_No response_

### Upload screenshots or videos

_No response_

### Additional Information

Regression introduced by https://github.com/FreeTubeApp/FreeTube/pull/7948
In this MR, a lot of strings are nullable, but are used with `str.includes(...)` which throws

### Nightly Build

- [x] I have encountered this bug in the latest **official** [nightly build](https://docs.freetubeapp.io/development/nightly-builds), do not check this box if you are using an unofficial or custom build.

Reproduce the issue using Settings > Distraction Free, the listed YouTube channel, and its Podcasts tab with the Invidious API. Then inspect the nullable string changes in PR #7948 and the renderer.js error path; done means the Podcasts tab no longer throws when a Hide Text value is set.

Written by the indexing model from the issue text.