bug(windows): When installed a kmp a link to a pdf in the readme.htm file does not display the .pdf.

### Describe the bug

When installing a .kmp, if the readme.htm has a link to a pdf in the package the pdf will not display.
The same link works if it's in the welcome.htm.

In addition, once I install the keyboard and go to OSK, Help button, I get the welcome.htm, but when I click on the link, it does not display the .pdf.

I would expect the pdf to display each time I click on the link.

### Reproduce the bug

1. Install https://keyman.com/keyboards/gautami_thamizh_tamil
2. Click on readme tab and then on the pdf link (it won't open)
3. Click on **Install**
a. Welcome.htm shows up.
b. Click on pdf link - below table (pdf shows)
4. Select keyboard
5. Select On-Screen keyboard
6. Click on question mark (welcome.htm displays)
7. Click on link for pdf below table (it won't open)
8. Go to C:\ProgramData\Keyman\Keyman Engine\Keyboard\_Package\gautami_thamizh_tamil
a. Open welcome.htm
b. Click on link to pdf and it opens

### Expected behavior

pdf should always show when you click on the link.

### Related issues

_No response_

### Keyman apps

- [ ] Keyman for Android
- [ ] Keyman for iPhone and iPad
- [ ] Keyman for Linux
- [ ] Keyman for macOS
- [X] Keyman for Windows
- [ ] Keyman Developer
- [ ] KeymanWeb
- [ ] Other - give details at bottom of form

### Keyman version

17.0.326

### Operating system

Windows 11

### Device

_No response_

### Target application

_No response_

### Browser

_No response_

### Keyboard name

gautami_thamizh_tamil

### Keyboard version

1.0

### Language name

Tamil

### Additional context