Update the copy on the Redemption page

Currently 3 hours is quite optimistic and it often takes around 5 hours
(experienced that during UATs several times). Here we update a copy
saying that a redemption takes `3-5 hours`.

src/pages/tBTC/Bridge/Unmint.tsx

@@ -101,7 +101,8 @@ const UnmintFormPage: PageComponent = ({}) => {
  subTitle="Unmint your tBTC tokens"
  />
  <BodyMd color="gray.500">
- Unminting requires one Ethereum transaction and it takes around 3 hours.
+ Unminting requires one Ethereum transaction and it takes around 3-5
+ hours.
  </BodyMd>
  <UnmintForm
  maxTokenAmount={balance.toString()}
@@ -122,7 +123,7 @@ const UnmintAsideLayout = () => {
  <LabelSm>Duration</LabelSm>
  <HStack mt="4" spacing="4">
  <BoxLabel variant="solid" status="primary">
- ~ 3 Hours
+ ~ 3-5 Hours
  </BoxLabel>
  <Box>
  <BodyXs as="span" color="gray.500">

src/pages/tBTC/Bridge/UnmintDetails.tsx

@@ -167,7 +167,7 @@ export const UnmintDetails: PageComponent = () => {
  left="50%"
  transform="translateX(-50%)"
  >
- usual duration - 3 hours
+ usual duration - 3-5 hours
  </Badge>
  <TimelineItem status="active">
  <TimelineBreakpoint>
@@ -236,7 +236,7 @@ export const UnmintDetails: PageComponent = () => {
  >
  <BodyMd mt="6" px="3.5" mb="10" alignSelf="flex-start">
  Your redemption request is being processed. This will take
- around 5 hours.
+ around 3-5 hours.
  </BodyMd>
  </BridgeProcessStep>
  )}