resolve_technique_factories silently drops selected techniques with no registered factory

[feiiiiii5]

Describe the bug

resolve_technique_factories() in pyrit/scenario/core/matrix_atomic_attack_builder.py silently drops selected techniques that have no registered factory:

return {
    technique.value: all_factories[technique.value]
    for technique in context.scenario_techniques
    if technique.value in all_factories
}

A scenario selecting techniques ["a", "b", "c"] where "b" lacks a factory runs with 2 of 3 techniques and gives no indication that the selection was partially ignored — the attack matrix silently shrinks.

The repo already warns on this exact semantic elsewhere: scenarios/adaptive/adaptive_scenario.py (~L260) logs a warning and records skipped techniques in skipped_incompatible when factory.create(...) fails. The matrix path just filters without any signal.

Steps/Code to Reproduce

Select a technique name that is not in the registry (e.g. via a scenario config typo) and call resolve_technique_factories; the returned dict omits it without any log output.

Expected Results

At minimum a warning listing the dropped selections, consistent with adaptive_scenario.py's handling — e.g.

missing = [t.value for t in context.scenario_techniques if t.value not in all_factories]
if missing:
    logger.warning(f"Selected techniques have no registered factory and will be skipped: {missing}")

Happy to open a PR with this plus a regression test if maintainers agree.

[feiiiiii5]

Confirmed — resolve_technique_factories() in pyrit/scenario/core/matrix_atomic_attack_builder.py filtered unregistered techniques without any signal (the docstring even said "silently dropped").

Opened #2466 which emits one aggregated warning naming each missing technique (deduplicated, selection order) before proceeding. Also added regression tests covering warn/no-warn/dedup behavior.