Fix ParticleContainer: amrex::Long pid

```
error: narrowing conversion from 'amrex::Long' (aka 'long') to signed type 'int' is implementation-defined [bugprone-narrowing-conversions,-warnings-as-errors]
```

Source/Particles/PhysicalParticleContainer.cpp

@@ -1080,10 +1080,10 @@ PhysicalParticleContainer::AddPlasma (PlasmaInjector const& plasma_injector, int
 
  // Max number of new particles. All of them are created,
  // and invalid ones are then discarded
- const int max_new_particles = Scan::ExclusiveSum(counts.size(), counts.data(), offset.data());
+ const amrex::Long max_new_particles = Scan::ExclusiveSum(counts.size(), counts.data(), offset.data());
 
  // Update NextID to include particles created in this function
- int pid;
+ amrex::Long pid;
 #ifdef AMREX_USE_OMP
 #pragma omp critical (add_plasma_nextid)
 #endif
@@ -1092,7 +1092,7 @@ PhysicalParticleContainer::AddPlasma (PlasmaInjector const& plasma_injector, int
  ParticleType::NextID(pid+max_new_particles);
  }
  WARPX_ALWAYS_ASSERT_WITH_MESSAGE(
- static_cast<amrex::Long>(pid) + static_cast<amrex::Long>(max_new_particles) < LongParticleIds::LastParticleID,
+ pid + max_new_particles < LongParticleIds::LastParticleID,
  "ERROR: overflow on particle id numbers");
 
  const int cpuid = ParallelDescriptor::MyProc();
@@ -1103,8 +1103,8 @@ PhysicalParticleContainer::AddPlasma (PlasmaInjector const& plasma_injector, int
  DefineAndReturnParticleTile(lev, grid_id, tile_id);
  }
 
- auto old_size = particle_tile.size();
- auto new_size = old_size + max_new_particles;
+ amrex::Long old_size = particle_tile.size();
+ amrex::Long new_size = old_size + max_new_particles;
  particle_tile.resize(new_size);
 
  auto& soa = particle_tile.GetStructOfArrays();
@@ -1639,10 +1639,10 @@ PhysicalParticleContainer::AddPlasmaFlux (PlasmaInjector const& plasma_injector,
 
  // Max number of new particles. All of them are created,
  // and invalid ones are then discarded
- const int max_new_particles = Scan::ExclusiveSum(counts.size(), counts.data(), offset.data());
+ const amrex::Long max_new_particles = Scan::ExclusiveSum(counts.size(), counts.data(), offset.data());
 
  // Update NextID to include particles created in this function
- int pid;
+ amrex::Long pid;
 #ifdef AMREX_USE_OMP
 #pragma omp critical (add_plasma_nextid)
 #endif
@@ -1651,15 +1651,15 @@ PhysicalParticleContainer::AddPlasmaFlux (PlasmaInjector const& plasma_injector,
  ParticleType::NextID(pid+max_new_particles);
  }
  WARPX_ALWAYS_ASSERT_WITH_MESSAGE(
- static_cast<amrex::Long>(pid) + static_cast<amrex::Long>(max_new_particles) < LongParticleIds::LastParticleID,
+ pid + max_new_particles < LongParticleIds::LastParticleID,
  "overflow on particle id numbers");
 
  const int cpuid = ParallelDescriptor::MyProc();
 
  auto& particle_tile = tmp_pc.DefineAndReturnParticleTile(0, grid_id, tile_id);
 
- auto old_size = particle_tile.size();
- auto new_size = old_size + max_new_particles;
+ amrex::Long old_size = particle_tile.size();
+ amrex::Long new_size = old_size + max_new_particles;
  particle_tile.resize(new_size);
 
  auto& soa = particle_tile.GetStructOfArrays();