Fix uploading of symbols to Mozilla. (#19130)
### Summary of the issue:
NVDA builds are intended to upload debug symbols to Mozilla. This makes
it easier to diagnose issues related to NVDA's in-process code in
Firefox (both crash analysis and profiling), which helps both projects.
Unfortunately, this broke years ago for various reasons.
### Description of user facing changes:
None.
### Description of developer facing changes:
Mozilla crash reports and profiles will show useful symbols for NVDA
code.
I haven't included a change log entry for NVDA because this doesn't
impact NVDA developers normally, only if they're working with Firefox.
### Description of development approach:
1. The version of dump_syms.exe in miscDeps from Google Breakpad is very
outdated and probably no longer works. Mozilla completely rewrote this a
few years ago. Download that from GitHub releases and use that instead.
2. mozillaSyms.py uses relative paths, but the script was moved in
bd6b99ea, which broke these paths. Update the script accordingly.
3. The structure of NVDA's lib directory has changed significantly in
the last few years. Furthermore, NVDA now supports more architectures
(arm64, arm64ec). Update mozillaSyms.py accordingly.
4. Remove some unnecessary actions from the uploadSymbols CI job.
### Testing strategy:
Confirmed that [symbols were uploaded successfully in a try
run](https://github.com/nvaccess/nvda/actions/runs/18735136393/job/53440453068).
### Known issues with pull request:
None.
