Merge branch 'fix/core/10605-app-context-copy-strip-markers' into fix/core/10615-10616-10617-core-surrogates-and-app-context-markers-and-memory-leak

Merge branch 'fix/core/10582-km_core_state_get_actions-idempotency' into fix/core/10605-app-context-copy-strip-markers

Merge branch 'chore/core/10520-hide-old-action-apis' into fix/core/10582-km_core_state_get_actions-idempotency

auto: increment master version to 17.0.261

chore(linux): Fix API check if lines got removed in .symbols file

docs(linux): Update sample settings

fix(linux): Fix path to artifacts when uploading to llso

Fixes #10615 (surrogate handling, km_core_state_context_set_if_needed).
Fixes #10616 (markers in app context, in unit tests)
Fixes #10617 (memory leak in replace_context).

The surrogate handling and markers in app context bugs were quite
tangled, so opted to fix those both together in one commit. The memory
leak was spotted while verifying the changes for surrogate handling.

Surrogates were not handled in is_context_unchanged, and opted to
refactor to work directly with km_core_context_item arrays rather than
continue with the string-based comparison, for simplicity.

While writing the corresponding unit tests, realised that the
app_context checks were incorrect in a number of existing tests, and so
fixed up the existing tests at the same time as writing up the new
tests. The only changes to core for this were to add assertions for the
app_context to ensure that markers are not inadvertently added.

chore(oem/fv): Update versions in keyboards.csv

Merge branch 'fix/core/10582-km_core_state_get_actions-idempotency' into fix/core/10605-app-context-copy-strip-markers

Merge branch 'chore/core/10520-hide-old-action-apis' into fix/core/10582-km_core_state_get_actions-idempotency

If lines got removed in the .symbols file we won't find the current
version number in the .symbols file. This change fixes the expectations.

Also, if a major API change happens during the Alpha cycle we don't expect
another API version increment if one already happened since we released
the stable version.

This change also adds some unit tests for the new functionality. These
can be run manually and won't run during CI builds.

Fixes #10453.

auto: increment master version to 17.0.260

Python debugger in vscode >= 1.86 now uses a different type.

With the new download-artifact version when using `merge-multiple:true`
all artifacts end up in the same directory. This change adjusts for that.

Another follow-up of #10577.

chore(linux): Update debian changelog 🍒

Fixes #10605.

chore(common): history missing message fixup

chore(common): Add entries from 16.0.145 HISTORY.md

Not sure why this is happening, nothing obvious in logs. Will monitor.

fix(linux): Fix version comparison

chore(linux): Use correct format specifier for `g_utf8_strlen`

chore(common): cancel earlier builds when new test builds triggered

Follow-up of #10577.

- Upgrade upload-artifact to v4.3.0
- Upgrade download-artifact to v4.1.1
- Upgrade checkout to v4.1.1
- Upgrade gha-deb-signing to v0.6

Closes #10385.

feat(core,developer): simplify markers 🙀

feat(core): ldml double marker, C++ side 🙀

feat(developer):  double markers once again 🙀

auto: increment master version to 17.0.259