Edit opacity from 0.8 to 0.5 and remove forBackdropFilter (#5291)

Update for #4836 

- edit primary and secondary transparency opacities from 0.8 to 0.5
- remove forBackdropFilter from themes
- update components referencing transparency/primary and
transparency/secondary to have the following backdrop-filter: blur(12px)
saturate(200%) contrast(50%) brightness(130%)

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Co-authored-by: Félix Malfait <felix.malfait@gmail.com>

packages/twenty-front/src/modules/ui/field/input/components/FieldTextAreaOverlay.tsx

@@ -1,10 +1,10 @@
 import styled from '@emotion/styled';
 
 const StyledFieldTextAreaOverlay = styled.div`
-  align-items: center;
-  backdrop-filter: blur(8px);
-  background: ${({ theme }) => theme.background.transparent.secondary};
   border-radius: ${({ theme }) => theme.border.radius.sm};
+  background: ${({ theme }) => theme.background.transparent.secondary};
+  backdrop-filter: blur(12px) saturate(200%) contrast(50%) brightness(130%);
+  align-items: center;
   display: flex;
   height: 32px;
   margin: -1px;