Revert "[Impeller] Turned on new blur." (flutter/engine#49062)
Reverts flutter/engine#48472
This is causing memory crashes in the device lab:
https://ci.chromium.org/ui/p/flutter/builders/prod/Mac_ios%20backdrop_filter_perf_ios__timeline_summary/14324/overview
```
[2023-12-14 15:55:20.660354] [STDOUT] stdout: [+1764 ms] Process 611 stopped
[2023-12-14 15:55:20.662620] [STDOUT] stdout: [ +2 ms] * thread #12, name = 'io.flutter.1.raster', stop reason = EXC_RESOURCE (RESOURCE_TYPE_MEMORY: high watermark memory limit exceeded) (limit=2098 MB)
[2023-12-14 15:55:20.662686] [STDOUT] stdout: [ ] frame #0: 0x0000000106705e78 Flutter`void std::_LIBCPP_ABI_NAMESPACE::allocator<impeller::Command>::construct[abi:v15000]<impeller::Command, impeller::Command>(impeller::Command*, impeller::Command&&) + 8
[2023-12-14 15:55:20.662784] [STDOUT] stdout: [ ] Flutter`std::_LIBCPP_ABI_NAMESPACE::allocator<impeller::Command>::construct[abi:v15000]<impeller::Command, impeller::Command>:
[2023-12-14 15:55:20.662883] [STDOUT] stdout: [ ] -> 0x106705e78 <+8>: str x8, [x0]
[2023-12-14 15:55:20.662932] [STDOUT] stdout: [ ] 0x106705e7c <+12>: ldr x8, [x1, #0x8]
[2023-12-14 15:55:20.663033] [STDOUT] stdout: [ ] 0x106705e80 <+16>: str x8, [x0, #0x8]
[2023-12-14 15:55:20.663097] [STDOUT] stdout: [ ] 0x106705e84 <+20>: ldr x8, [x1, #0x10]
[2023-12-14 15:55:20.663194] [STDOUT] stdout: [ ] Target 0: (Runner) stopped.
[2023-12-14 15:55:20.663309] [STDOUT] stdout: [ ] thread backtrace all
[2023-12-14 15:55:20.663403] [STDOUT] stdout: [ ] process detach
```
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