R adbcdrivermanager truncates manifest search failure message

### What happened?

When I try to load a driver that I know the driver manager won't find, it produces the debug message I expect but truncates it:

```
> library(adbcdrivermanager)
> drv <- adbc_driver("some_driver")
Error in adbc_driver("some_driver") :
NOT_FOUND: [Driver Manager] dlopen() failed: dlopen(some_driver, 0x0006): tried: 'some_driver' (no such file), '/System/Volumes/Preboot/Cryptexes/OSsome_driver' (no such file), '/usr/lib/some_driver' (no such file, not in dyld cache), 'some_driver' (no such file), '/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/some_driver' (no such file), '/Library/Java/JavaVirtualMachines/jdk-11.0.18+10/Contents/Home/lib/server/some_driver' (no such file)
dlopen() failed: dlopen(libsome_driver.dylib, 0x0006): tried: 'libsome_driver.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibsome_driver.dylib' (no such file), '/usr/lib/libsome_driver.dylib' (no such file, not in dyld cache), 'libsome_driver.dylib' (no such file), '/Library/Frameworks/R.framework/Versions/4.5-arm64/Resources/lib/libsome_driver.dylib' (no such file), '/Library/Java/JavaVirtualMachines/jdk-11.0.18+10/Contents/Home/lib/server/libsome_driver.dylib' (no such file)
Also searched these paths for manifests:
not set: ADBC_DR
```

From Python, we can see the entire message:

```python
-- >8 --
Also searched these paths for manifests:
not set: ADBC_DRIVER_PATH
additional search path: /Users/bryce/.cache/uv/builds-v0/.tmpeFNFZ4/etc/adbc
not enabled at build time: Conda prefix
user config dir: /Users/bryce/Library/Application Support/ADBC/Drivers
does not exist: /Library/Application Support/ADBC/Drivers
```

### Stack Trace

_No response_

### How can we reproduce the bug?

_No response_

### Environment/Setup

- macOS 15
- R 4.5.1
- adbc_driver_manager 0.20.0

Start by reproducing the library(adbcdrivermanager) and adbc_driver("some_driver") call on the reported macOS and R setup, then compare its error output with the complete Python message shown in the issue. Done means the R error includes the full manifest search failure details, including all searched paths.

Written by the indexing model from the issue text.