Compile tzdata if compiled dir is empty

[omus]

Interactive test:

julia> using Revise, TimeZones

julia> TimeZones.build("2024b")
[ Info: Compiling tzdata 2024b region data
ERROR: KeyError: key "April" not found
Stacktrace:
  [1] getindex
    @ ./dict.jl:498 [inlined]
  [2] parse(::Type{TimeZones.TZData.Rule}, str::SubString{String})
    @ TimeZones.TZData ~/.julia/dev/TimeZones/src/tzdata/compile.jl:301
  [3] load!(tz_source::TimeZones.TZData.TZSource, filename::String, io::IOStream)
    @ TimeZones.TZData ~/.julia/dev/TimeZones/src/tzdata/compile.jl:615
  [4] #34
    @ ~/.julia/dev/TimeZones/src/tzdata/compile.jl:636 [inlined]
  [5] open(::TimeZones.TZData.var"#34#35"{TimeZones.TZData.TZSource, String}, ::String, ::Vararg{String}; kwargs::@Kwargs{})
    @ Base ./io.jl:396
  [6] open
    @ ./io.jl:393 [inlined]
  [7] load!
    @ ~/.julia/dev/TimeZones/src/tzdata/compile.jl:635 [inlined]
  [8] TimeZones.TZData.TZSource(files::Vector{String})
    @ TimeZones.TZData ~/.julia/dev/TimeZones/src/tzdata/compile.jl:71
  [9] build(version::String, working_dir::String)
    @ TimeZones.TZData ~/.julia/dev/TimeZones/src/tzdata/build.jl:59
 [10] build(version::String; force::Bool)
    @ TimeZones ~/.julia/dev/TimeZones/src/build.jl:12
 [11] build(version::String)
    @ TimeZones ~/.julia/dev/TimeZones/src/build.jl:11
 [12] top-level scope
    @ REPL[2]:1

julia> TimeZones.build("2024b") # Introduced KeyError fix
ERROR: Cache remains empty after loading
Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:35
 [2] reload!
   @ ~/.julia/dev/TimeZones/src/types/timezonecache.jl:40 [inlined]
 [3] _reload_tz_cache
   @ ~/.julia/dev/TimeZones/src/types/timezonecache.jl:73 [inlined]
 [4] build(version::String; force::Bool)
   @ TimeZones ~/.julia/dev/TimeZones/src/build.jl:16
 [5] build(version::String)
   @ TimeZones ~/.julia/dev/TimeZones/src/build.jl:11
 [6] top-level scope
   @ REPL[3]:1

julia> TimeZones.build("2024b") # Introduced compiled dir fix
[ Info: Compiling tzdata 2024b region data
[ Info: Successfully built TimeZones