Fix failing macOS DNS tests, and truncate log files in tests

[dlon]

Changes:

• Fetch tags when checking out code in GH Actions (so that ci-runtests.sh can recognize tags).
• Make sure tests don't leave any lingering tokio tasks that were spawned.
• Cache UI runners.
• Truncate log files before transferring them and ignore .old.log files.
• Fix failing DNS leak tests on macOS

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This change is 

[MarkusPettersson98]

Reviewed 4 of 6 files at r1, 3 of 3 files at r2, all commit messages.
Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @dlon)

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.github/workflows/desktop-e2e.yml line 6 at r2 (raw file):

    - cron: '0 0 * * *'
  workflow_dispatch:
  push:

Remove before merge

Code quote:

push:

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test/ci-runtests.sh line 36 at r2 (raw file):

#NEW_APP_VERSION=$(cargo run -q --manifest-path="$APP_DIR/Cargo.toml" --bin mullvad-version)
#commit=$(git rev-parse HEAD^\{commit\})
#commit=${commit:0:6}

Revert before merge

Code quote:

NEW_APP_VERSION=2023.5-dev-03feae
commit=03feae
#NEW_APP_VERSION=$(cargo run -q --manifest-path="$APP_DIR/Cargo.toml" --bin mullvad-version)
#commit=$(git rev-parse HEAD^\{commit\})
#commit=${commit:0:6}

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test/test-runner/src/logging.rs line 22 at r2 (raw file):

const EXCLUDE_LOG_FILE_CONTAIN: &str = ".old";
/// Maximum number of lines that each log file may contain
const TRUNCATE_LOG_FILE_LINES: usize = 100;

This could be more general/configurable, but good enough for now:D

Code quote:

/// Only consider files that end with ".log"
const INCLUDE_LOG_FILE_EXT: &str = "log";
/// Ignore log files that contain ".old"
const EXCLUDE_LOG_FILE_CONTAIN: &str = ".old";
/// Maximum number of lines that each log file may contain
const TRUNCATE_LOG_FILE_LINES: usize = 100;

[MarkusPettersson98]

Reviewed 2 of 2 files at r3, all commit messages.
Reviewable status: all files reviewed, 3 unresolved discussions (waiting on @dlon)