Updated tent panel slider for ie8

https://www.pivotaltracker.com/s/projects/896548/stories/56213194
Old PR. #399
### RootCause
1.Height shifting issue on IE8 when two panel slider open 

### Resolutions
1.Added auto height when browser is IE8

### Test
Mocha

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__General Requirements__
- [ ] Pull Request contains full description of changes
- [ ] Link to the Pivotal Tracker story
- [ ] Pivotal Tracker story has a reference to this Pull Request
- [ ] Rebased against latest master branch
- [ ] All comments from code review have been addressed
- [ ] There are no `-1` code reviews (can only be overridden by Kyle)

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__Coding Standards__
- [ ] Style guidelines are followed, code has been formatted
- [ ] Code follows idiomatic language paradigms

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__Testing__
- [ ] Test coverage has not decreased
- [ ] There is no performance degradation
- [ ] All appropriate automated tests are present
- [ ] Appropriate seed data exists

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__UI/UX__
- [ ] applicable (UI/UX has been changed)
- [ ] reviewed for usability and design
- [ ] functions on 1024*768 browser size
- [ ] works on IE8 (presently only required for SCiCustomer)

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__Defect__
- [ ] Feature or defect resolution has been manually tested and meets all requirements of the underlying story
- [ ] Seed data sufficient to satisfy testing resolution of defect
- [ ] Root cause analysis provided